The Enzyme Database

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EC 2.4.1.386     Relevance: 100%
Accepted name: GlcNAc-β-1,3-Gal β-1,6-N-acetylglucosaminyltransferase (distally acting)
Reaction: UDP-N-acetyl-α-D-glucosamine + β-D-GlcNAc-(1→3)-β-D-Gal-(1→4)-β-D-GlcNAc-R = UDP + β-D-GlcNAc-(1→3)-[β-D-GlcNAc-(1→6)]-β-D-Gal-(1→4)-β-D-GlcNAc-R
Other name(s): UDP-GlcNAc:GlcNAcβ1-3Gal(-R) β1-6(GlcNAc to Gal) N-acetylglucosaminyltransferase; dIGnT; C2GnT2 (misleading)
Systematic name: UDP-N-acetyl-α-D-glucosamine:N-acetyl-β-D-glucosaminyl-(1→3)-β-D-galactosyl-(1→4)-N-acetyl-β-D-glucosaminide 6-β-N-acetylglucosaminyltransferase (configuration-inverting)
Comments: Involved in the production of milk oligosaccharides in the lacto-N-triose (LNT) series. Cf. EC 2.4.1.150 (N-acetyllactosaminide β-1,6-N-acetylglucosaminyltransferase; cIGnT) and EC 2.4.1.148 (acetylgalactosaminyl-O-glycosyl-glycoprotein β-1,6-N-acetylglucosaminyltransferase).
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc, CAS registry number: 85638-40-0
References:
1.  Piller, F., Cartron, J.P., Maranduba, A., Veyrieres, A., Leroy, Y. and Fournet, B. Biosynthesis of blood group I antigens. Identification of a UDP-GlcNAc:GlcNAc β1-3Gal(-R) β1-6(GlcNAc to Gal) N-acetylglucosaminyltransferase in hog gastric mucosa. J. Biol. Chem. 259 (1984) 13385–13390. [PMID: 6490658]
2.  Yeh, J.C., Ong, E. and Fukuda, M. Molecular cloning and expression of a novel β-1,6-N-acetylglucosaminyltransferase that forms core 2, core 4, and I branches. J. Biol. Chem. 274 (1999) 3215–3221. [DOI] [PMID: 9915862]
[EC 2.4.1.386 created 2021]
 
 
EC 3.2.1.140     Relevance: 97.2%
Accepted name: lacto-N-biosidase
Reaction: β-D-Gal-(1→3)-β-D-GlcNAc-(1→3)-β-D-Gal-(1→4)-D-Glc + H2O = β-D-Gal-(1→3)-D-GlcNAc + β-D-Gal-(1→4)-D-Glc
Glossary: β-D-Gal-(1→3)-β-D-GlcNAc-(1→3)-β-D-Gal-(1→4)-D-Glc = lacto-N-tetraose
β-D-Gal-(1→3)-D-GlcNAc = lacto-N-biose
β-D-Gal-(1→4)-D-Glc = lactose
Systematic name: oligosaccharide lacto-N-biosylhydrolase
Comments: The enzyme from Streptomyces specifically hydrolyses the terminal lacto-N-biosyl residue (β-D-Gal-(1→3)-D-GlcNAc) from the non-reducing end of oligosaccharides with the structure β-D-Gal-(1→3)-β-D-GlcNAc-(1→3)-β-D-Gal-(1→R). Lacto-N-hexaose (β-D-Gal-(1→3)-β-D-GlcNAc-(1→3)-β-D-Gal-(1→3)-β-D-GlcNAc-(1→3)-β-D-Gal-(1→4)-D-Glc) is hydrolysed to form first lacto-N-tetraose plus lacto-N-biose, with the subsequent formation of lactose. Oligosaccharides in which the non-reducing terminal Gal or the penultimate GlcNAc are replaced by fucose or sialic acid are not substrates. Asialo GM1 tetraose (β-D-Gal-(1→3)-β-D-GalNAc-(1→3)-β-D-Gal-(1→4)-D-Glc) is hydrolysed very slowly, but lacto-N-neotetraose (β-D-Gal-(1→4)-β-D-GalNAc-(1→3)-β-D-Gal-(1→4)-D-Glc) is not a substrate
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc, CAS registry number: 146359-52-6
References:
1.  Sano, M., Hayakawa, K., Kato, I. An enzyme releasing lacto-N-biose from oligosaccharides. Proc. Natl. Acad. Sci. USA 89 (1992) 8512–8516. [DOI] [PMID: 1528855]
2.  Sano, M., Hayakawa, K., Kato, I. Purification and characterization of an enzyme releasing lacto-N-biose from oligosaccharides with type 1 chain. J. Biol. Chem. 268 (1993) 18560–18566. [PMID: 7689556]
[EC 3.2.1.140 created 1999]
 
 
EC 2.4.1.201     Relevance: 95.2%
Accepted name: α-1,6-mannosyl-glycoprotein 4-β-N-acetylglucosaminyltransferase
Reaction: UDP-N-acetyl-α-D-glucosamine + β-D-GlcNAc-(1→2)-[β-D-GlcNAc-(1→4)]-α-D-Man-(1→3)-[β-D-GlcNAc-(1→2)-[β-D-GlcNAc-(1→6)]-α-D-Man-(1→6)]-β-D-Man-(1→4)-β-D-GlcNAc-(1→4)-β-D-GlcNAc-N-Asn-[protein] = UDP + β-D-GlcNAc-(1→2)-[β-D-GlcNAc-(1→4)]-α-D-Man-(1→3)-[β-D-GlcNAc-(1→2)-[β-D-GlcNAc-(1→4)]-[β-D-GlcNAc-(1→6)]-α-D-Man-(1→6)]-β-D-Man-(1→4)-β-D-GlcNAc-(1→4)-β-D-GlcNAc-N-Asn-[protein]
For diagram of mannosyl-glycoprotein n-acetylglucosaminyltransferases, click here
Other name(s): MGAT4C (gene name); N-acetylglucosaminyltransferase VI; N-glycosyl-oligosaccharide-glycoprotein N-acetylglucosaminyltransferase VI; uridine diphosphoacetylglucosamine-glycopeptide β-1→4-acetylglucosaminyltransferase VI; mannosyl-glycoprotein β-1,4-N-acetylglucosaminyltransferase; GnTVI; GlcNAc-T VI; UDP-N-acetyl-D-glucosamine:2,6-bis(N-acetyl-β-D-glucosaminyl)-α-D-mannosyl-glycoprotein 4-β-N-acetyl-D-glucosaminyltransferase
Systematic name: UDP-N-acetyl-α-D-glucosamine:N-acetyl-β-D-glucosaminyl-(1→6)-[N-acetyl-β-D-glucosaminyl-(1→2)]-α-D-mannosyl-glycoprotein 4-β-N-acetyl-D-glucosaminyltransferase (configuration-inverting)
Comments: Requires a high concentration of Mn2+ for maximal activity. The enzyme, characterized from hen oviduct membranes, participates in the processing of N-glycans in the Golgi apparatus. It transfers GlcNAc in β1-4 linkage to a D-mannose residue that already has GlcNAc residues attached at positions 2 and 6 by β linkages. No homologous enzyme appears to exist in mammals.
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc, CAS registry number: 119699-68-2
References:
1.  Brockhausen, I., Hull, E., Hindsgaul, O., Schachter, H., Shah, R.N., Michnick, S.W. and Carver, J.P. Control of glycoprotein synthesis. Detection and characterization of a novel branching enzyme from hen oviduct, UDP-N-acetylglucosamine:GlcNAc β1-6 (GlcNAc β1-2)Man α-R (GlcNAc to Man) β-4-N-acetylglucosaminyltransferase VI. J. Biol. Chem. 264 (1989) 11211–11221. [PMID: 2525556]
2.  Taguchi, T., Ogawa, T., Inoue, S., Inoue, Y., Sakamoto, Y., Korekane, H. and Taniguchi, N. Purification and characterization of UDP-GlcNAc:GlcNAcβ1-6(GlcNAcβ1-2)Manα1-R [GlcNAc to Man]-β1,4-N-acetylglucosaminyltransferase VI from hen oviduct. J. Biol. Chem. 275 (2000) 32598–32602. [DOI] [PMID: 10903319]
3.  Sakamoto, Y., Taguchi, T., Honke, K., Korekane, H., Watanabe, H., Tano, Y., Dohmae, N., Takio, K., Horii, A. and Taniguchi, N. Molecular cloning and expression of cDNA encoding chicken UDP-N-acetyl-D-glucosamine (GlcNAc): GlcNAcβ 1-6(GlcNAcβ 1-2)- manα 1-R[GlcNAc to man]β 1,4N-acetylglucosaminyltransferase VI. J. Biol. Chem. 275 (2000) 36029–36034. [DOI] [PMID: 10962001]
[EC 2.4.1.201 created 1992, modified 2001, modified 2018]
 
 
EC 2.4.1.144     Relevance: 91.1%
Accepted name: β-1,4-mannosyl-glycoprotein 4-β-N-acetylglucosaminyltransferase
Reaction: UDP-N-acetyl-α-D-glucosamine + β-D-GlcNAc-(1→2)-α-D-Man-(1→3)-[β-D-GlcNAc-(1→2)-α-D-Man-(1→6)]-β-D-Man-(1→4)-β-D-GlcNAc-(1→4)-β-D-GlcNAc-N-Asn-[protein] = UDP + β-D-GlcNAc-(1→2)-α-D-Man-(1→3)-[β-D-GlcNAc-(1→2)-α-D-Man-(1→6)]-[β-D-GlcNAc-(1→4)]-β-D-Man-(1→4)-β-D-GlcNAc-(1→4)-β-D-GlcNAc-N-Asn-[protein]
For diagram of mannosyl-glycoprotein N-acetylglucosaminyltransferases, click here
Other name(s): N-acetylglucosaminyltransferase III; N-glycosyl-oligosaccharide-glycoprotein N-acetylglucosaminyltransferase III; uridine diphosphoacetylglucosamine-glycopeptide β4-acetylglucosaminyltransferase III; β-1,4-mannosyl-glycoprotein β-1,4-N-acetylglucosaminyltransferase; GnTIII; GlcNAc-T III; MGAT3 (gene name); UDP-N-acetyl-D-glucosamine:β-D-mannosyl-glycoprotein 4-β-N-acetyl-D-glucosaminyltransferase
Systematic name: UDP-N-acetyl-α-D-glucosamine:β-D-mannosyl-glycoprotein 4-β-N-acetyl-D-glucosaminyltransferase (configuration-inverting)
Comments: The enzyme, found in vertebrates, participates in the processing of N-glycans in the Golgi apparatus. The residue added by the enzyme at position 4 of the β-linked mannose of the trimannosyl core of N-glycans is known as a bisecting GlcNAc. Unlike GlcNAc residues added to other positions, it is not extended or modified. In addition, its presence prevents the action of other branching enzymes involved in the process such as GlcNAc-T IV (EC 2.4.1.145) and GlcNAc-T V (EC 2.4.1.155), and thus increased activity of GlcNAc-T III leads to a decrease in highly branched N-glycan structures.
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc, CAS registry number: 83744-93-8
References:
1.  Narasimhan, S. Control of glycoprotein synthesis. UDP-GlcNAc:glycopeptide β4-N-acetylglucosaminyltransferase III, an enzyme in hen oviduct which adds GlcNAc in β1-4 linkage to the β-linked mannose of the trimannosyl core of N-glycosyl oligosaccharides. J. Biol. Chem. 257 (1982) 10235–10242. [PMID: 6213618]
2.  Schachter, H., Narasimhan, S., Gleeson, P. and Vella, G. Glycosyltransferases involved in elongation of N-glycosidically linked oligosaccharides of the complex or N-acetyllactosamine type. Methods Enzymol. 98 (1983) 98–134. [PMID: 6366476]
3.  Brockhausen, I., Carver, J.P. and Schachter, H. Control of glycoprotein synthesis. The use of oligosaccharide substrates and HPLC to study the sequential pathway for N-acetylglucosaminyltransferases I, II, III, IV, V, and VI in the biosynthesis of highly branched N-glycans by hen oviduct membranes. Biochem. Cell Biol. 66 (1988) 1134–1151. [PMID: 2975180]
4.  Nishikawa, A., Ihara, Y., Hatakeyama, M., Kangawa, K. and Taniguchi, N. Purification, cDNA cloning, and expression of UDP-N-acetylglucosamine: β-D-mannoside β-1,4N-acetylglucosaminyltransferase III from rat kidney. J. Biol. Chem. 267 (1992) 18199–18204. [PMID: 1325461]
5.  Ihara, Y., Nishikawa, A., Tohma, T., Soejima, H., Niikawa, N. and Taniguchi, N. cDNA cloning, expression, and chromosomal localization of human N-acetylglucosaminyltransferase III (GnT-III). J. Biochem. 113 (1993) 692–698. [PMID: 8370666]
[EC 2.4.1.144 created 1984, modified 2001 (EC 2.4.1.51 created 1972, part incorporated 1984), modified 2018]
 
 
EC 2.4.1.155     Relevance: 88.4%
Accepted name: α-1,6-mannosyl-glycoprotein 6-β-N-acetylglucosaminyltransferase
Reaction: UDP-N-acetyl-α-D-glucosamine + β-D-GlcNAc-(1→2)-[β-D-GlcNAc-(1→4)]-α-D-Man-(1→3)-[β-D-GlcNAc-(1→2)-α-D-Man-(1→6)]-β-D-Man-(1→4)-β-D-GlcNAc-(1→4)-β-D-GlcNAc-N-Asn-[protein] = UDP + β-D-GlcNAc-(1→2)-[β-D-GlcNAc-(1→4)]-α-D-Man-(1→3)-[β-D-GlcNAc-(1→2)-[β-D-GlcNAc-(1→6)]-α-D-Man-(1→6)]-β-D-Man-(1→4)-β-D-GlcNAc-(1→4)-β-D-GlcNAc-N-Asn-[protein]
For diagram of mannosyl-glycoprotein n-acetylglucosaminyltransferases, click here
Other name(s): MGAT5 (gene name); N-acetylglucosaminyltransferase V; α-mannoside β-1,6-N-acetylglucosaminyltransferase; uridine diphosphoacetylglucosamine-α-mannoside β1→6-acetylglucosaminyltransferase; UDP-N-acetylglucosamine:α-mannoside-β1,6 N-acetylglucosaminyltransferase; α-1,3(6)-mannosylglycoprotein β-1,6-N-acetylglucosaminyltransferase; GnTV; GlcNAc-T V; UDP-N-acetyl-D-glucosamine:6-[2-(N-acetyl-β-D-glucosaminyl)-α-D-mannosyl]-glycoprotein 6-β-N-acetyl-D-glucosaminyltransferase
Systematic name: UDP-N-acetyl-α-D-glucosamine:N-acetyl-β-D-glucosaminyl-(1→2)-α-D-mannosyl-(1→6)-β-D-mannosyl-glycoprotein 6-β-N-acetyl-D-glucosaminyltransferase (configuration-inverting)
Comments: Requires Mg2+. The enzyme, found in vertebrates, participates in the processing of N-glycans in the Golgi apparatus. It catalyses the addition of N-acetylglucosamine in β 1-6 linkage to the α-linked mannose of biantennary N-linked oligosaccharides, and thus enables the synthesis of tri- and tetra-antennary complexes.
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc, CAS registry number: 83588-90-3
References:
1.  Cummings, R.D., Trowbridge, I.S. and Kornfeld, S. A mouse lymphoma cell line resistant to the leukoagglutinating lectin from Phaseolus vulgaris is deficient in UDP-GlcNAc: α-D-mannoside β1,6 N-acetylglucosaminyltransferase. J. Biol. Chem. 257 (1982) 13421–13427. [PMID: 6216250]
2.  Hindsgaul, O., Tahir, S.H., Srivastava, O.P. and Pierce, M. The trisaccharide β-D-GlcpNAc-(1→2)-α-D-Manp-(1→6)-β-D-Manp, as its 8-methoxycarbonyloctyl glycoside, is an acceptor selective for N-acetylglucosaminyltransferase V. Carbohydr. Res. 173 (1988) 263–272. [DOI] [PMID: 2834054]
3.  Shoreibah, M.G., Hindsgaul, O. and Pierce, M. Purification and characterization of rat kidney UDP-N-acetylglucosamine: α-6-D-mannoside β-1,6-N-acetylglucosaminyltransferase. J. Biol. Chem. 267 (1992) 2920–2927. [PMID: 1531335]
4.  Gu, J., Nishikawa, A., Tsuruoka, N., Ohno, M., Yamaguchi, N., Kangawa, K. and Taniguchi, N. Purification and characterization of UDP-N-acetylglucosamine: α-6-D-mannoside β 1-6N-acetylglucosaminyltransferase (N-acetylglucosaminyltransferase V) from a human lung cancer cell line. J. Biochem. 113 (1993) 614–619. [PMID: 8393437]
5.  Park, C., Jin, U.H., Lee, Y.C., Cho, T.J. and Kim, C.H. Characterization of UDP-N-acetylglucosamine:α-6-D-mannoside β-1,6-N-acetylglucosaminyltransferase V from a human hepatoma cell line Hep3B. Arch. Biochem. Biophys. 367 (1999) 281–288. [PMID: 10395745]
6.  Saito, T., Miyoshi, E., Sasai, K., Nakano, N., Eguchi, H., Honke, K. and Taniguchi, N. A secreted type of β 1,6-N-acetylglucosaminyltransferase V (GnT-V) induces tumor angiogenesis without mediation of glycosylation: a novel function of GnT-V distinct from the original glycosyltransferase activity. J. Biol. Chem. 277 (2002) 17002–17008. [PMID: 11872751]
[EC 2.4.1.155 created 1986, modified 2001, modified 2018]
 
 
EC 2.4.1.145     Relevance: 86.1%
Accepted name: α-1,3-mannosyl-glycoprotein 4-β-N-acetylglucosaminyltransferase
Reaction: UDP-N-acetyl-α-D-glucosamine + β-D-GlcNAc-(1→2)-α-D-Man-(1→3)-[β-D-GlcNAc-(1→2)-α-D-Man-(1→6)]-β-D-Man-(1→4)-β-D-GlcNAc-(1→4)-β-D-GlcNAc-N-Asn-[protein] = UDP + β-D-GlcNAc-(1→2)-[β-D-GlcNAc-(1→4)]-α-D-Man-(1→3)-[β-D-GlcNAc-(1→2)-α-D-Man-(1→6)]-β-D-Man-(1→4)-β-D-GlcNAc-(1→4)-β-D-GlcNAc-N-Asn-[protein]
For diagram of mannosyl-glycoprotein N-acetylglucosaminyltransferases, click here
Other name(s): N-acetylglucosaminyltransferase IV; N-glycosyl-oligosaccharide-glycoprotein N-acetylglucosaminyltransferase IV; β-acetylglucosaminyltransferase IV; uridine diphosphoacetylglucosamine-glycopeptide β4-acetylglucosaminyltransferase IV; α-1,3-mannosylglycoprotein β-1,4-N-acetylglucosaminyltransferase; GnTIV; UDP-N-acetyl-D-glucosamine:3-[2-(N-acetyl-β-D-glucosaminyl)-α-D-mannosyl]-glycoprotein 4-β-N-acetyl-D-glucosaminyltransferase
Systematic name: UDP-N-acetyl-α-D-glucosamine:N-acetyl-β-D-glucosaminyl-(1→2)-α-D-mannosyl-(1→3)-β-D-mannosyl-glycoprotein 4-β-N-acetyl-D-glucosaminyltransferase (configuration-inverting)
Comments: Requires Mn2+. The enzyme, found in vertebrates, participates in the processing of N-glycans in the Golgi apparatus. By adding a glucosaminyl residue to biantennary N-linked glycans, it enables the synthesis of tri- and tetra-antennary complexes.
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc, CAS registry number: 86498-16-0
References:
1.  Gleeson, P.A. and Schachter, H. Control of glycoprotein synthesis. J. Biol. Chem. 258 (1983) 6162–6173. [PMID: 6222042]
2.  Oguri, S., Minowa, M.T., Ihara, Y., Taniguchi, N., Ikenaga, H. and Takeuchi, M. Purification and characterization of UDP-N-acetylglucosamine: α1,3-D-mannoside β1,4-N-acetylglucosaminyltransferase (N-acetylglucosaminyltransferase-IV) from bovine small intestine. J. Biol. Chem. 272 (1997) 22721–22727. [DOI] [PMID: 9278430]
3.  Minowa, M.T., Oguri, S., Yoshida, A., Hara, T., Iwamatsu, A., Ikenaga, H. and Takeuchi, M. cDNA cloning and expression of bovine UDP-N-acetylglucosamine: α1, 3-D-mannoside β1,4-N-acetylglucosaminyltransferase IV. J. Biol. Chem. 273 (1998) 11556–11562. [DOI] [PMID: 9565571]
4.  Yoshida, A., Minowa, M.T., Takamatsu, S., Hara, T., Oguri, S., Ikenaga, H. and Takeuchi, M. Tissue specific expression and chromosomal mapping of a human UDP-N-acetylglucosamine: α1,3-d-mannoside β1, 4-N-acetylglucosaminyltransferase. Glycobiology 9 (1999) 303–310. [DOI] [PMID: 10024668]
5.  Yoshida, A., Minowa, M.T., Takamatsu, S., Hara, T., Ikenaga, H. and Takeuchi, M. A novel second isoenzyme of the human UDP-N-acetylglucosamine:α1,3-D-mannoside β1,4-N-acetylglucosaminyltransferase family: cDNA cloning, expression, and chromosomal assignment. Glycoconj. J. 15 (1998) 1115–1123. [PMID: 10372966]
6.  Takamatsu, S., Antonopoulos, A., Ohtsubo, K., Ditto, D., Chiba, Y., Le, D.T., Morris, H.R., Haslam, S.M., Dell, A., Marth, J.D. and Taniguchi, N. Physiological and glycomic characterization of N-acetylglucosaminyltransferase-IVa and -IVb double deficient mice. Glycobiology 20 (2010) 485–497. [DOI] [PMID: 20015870]
[EC 2.4.1.145 created 1984, modified 2001 (EC 2.4.1.51 created 1972, part incorporated 1984), modified 2018]
 
 
EC 2.4.1.132     Relevance: 85.7%
Accepted name: GDP-Man:Man1GlcNAc2-PP-dolichol α-1,3-mannosyltransferase
Reaction: GDP-α-D-mannose + β-D-Man-(1→4)-β-D-GlcNAc-(1→4)-α-D-GlcNAc-diphosphodolichol = GDP + α-D-Man-(1→3)-β-D-Man-(1→4)-β-D-GlcNAc-(1→4)-α-D-GlcNAc-diphosphodolichol
For diagram of dolichyltetradecasaccharide biosynthesis, click here
Glossary: β-D-Man-(1→4)-β-D-GlcNAc-(1→4)-α-D-GlcNAc-diphosphodolichol = β-D-mannosyl-(1→4)-N,N′-diacetylchitobiosyldiphosphodolichol
Other name(s): Alg2 mannosyltransferase (ambiguous); ALG2 (gene name, ambiguous); glycolipid 3-α-mannosyltransferase; GDP-mannose:glycolipid 3-α-D-mannosyltransferase; GDP-Man:Man1GlcNAc2-PP-Dol α-1,3-mannosyltransferase; GDP-D-mannose:D-Man-β-(1→4)-D-GlcNAc-β-(1→4)-D-GlcNAc-diphosphodolichol 3-α-mannosyltransferase
Systematic name: GDP-α-D-mannose:β-D-Man-(1→4)-β-D-GlcNAc-(1→4)-α-D-GlcNAc-diphosphodolichol 3-α-D-mannosyltransferase (configuration-retaining)
Comments: The biosynthesis of asparagine-linked glycoproteins utilizes a dolichyl diphosphate-linked glycosyl donor, which is assembled by the series of membrane-bound glycosyltransferases that comprise the dolichol pathway. Alg2 mannosyltransferase from Saccharomyces cerevisiae carries out an α1,3-mannosylation of D-Man-β-(1→4)-D-GlcNAc-β-(1→4)-D-GlcNAc-diphosphodolichol, followed by an α1,6-mannosylation (cf. EC 2.4.1.257), to form the first branched pentasaccharide intermediate of the dolichol pathway [1,2].
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc, CAS registry number: 81181-76-2
References:
1.  Kampf, M., Absmanner, B., Schwarz, M. and Lehle, L. Biochemical characterization and membrane topology of Alg2 from Saccharomyces cerevisiae as a bifunctional α1,3- and 1,6-mannosyltransferase involved in lipid-linked oligosaccharide biosynthesis. J. Biol. Chem. 284 (2009) 11900–11912. [DOI] [PMID: 19282279]
2.  O'Reilly, M.K., Zhang, G. and Imperiali, B. In vitro evidence for the dual function of Alg2 and Alg11: essential mannosyltransferases in N-linked glycoprotein biosynthesis. Biochemistry 45 (2006) 9593–9603. [DOI] [PMID: 16878994]
[EC 2.4.1.132 created 1984, modified 2011, modified 2012]
 
 
EC 2.4.2.38     Relevance: 85.4%
Accepted name: glycoprotein 2-β-D-xylosyltransferase
Reaction: UDP-α-D-xylose + N4-{β-D-GlcNAc-(1→2)-α-D-Man-(1→3)-[β-D-GlcNAc-(1→2)-α-D-Man-(1→6)]-β-D-Man-(1→4)-β-D-GlcNAc-(1→4)-β-D-GlcNAc}-L-asparaginyl-[protein] = UDP + N4-{β-D-GlcNAc-(1→2)-α-D-Man-(1→3)-[β-D-GlcNAc-(1→2)-α-D-Man-(1→6)]-[β-D-Xyl-(1→2)]-β-D-Man-(1→4)-β-D-GlcNAc-(1→4)-β-D-GlcNAc}-L-asparaginyl-[protein]
For diagram of mannosyl-glycoprotein fucosyl and xylosyl transferases, click here
Other name(s): β1,2-xylosyltransferase; UDP-D-xylose:glycoprotein (D-xylose to the 3,6-disubstituted mannose of 4-N-{N-acetyl-β-D-glucosaminyl-(1→2)-α-D-mannosyl-(1→3)-[N-acetyl-β-D-glucosaminyl-(1→2)-α-D-mannosyl-(1→6)]-β-D-mannosyl-(1→4)-N-acetyl-β-D-glucosaminyl-(1→4)-N-acetyl-β-D-glucosaminyl}asparagine) 2-β-D-xylosyltransferase; UDP-D-xylose:glycoprotein (D-xylose to the 3,6-disubstituted mannose of N4-{N-acetyl-β-D-glucosaminyl-(1→2)-α-D-mannosyl-(1→3)-[N-acetyl-β-D-glucosaminyl-(1→2)-α-D-mannosyl-(1→6)]-β-D-mannosyl-(1→4)-N-acetyl-β-D-glucosaminyl-(1→4)-N-acetyl-β-D-glucosaminyl}asparagine) 2-β-D-xylosyltransferase
Systematic name: UDP-α-D-xylose:N4-{β-D-GlcNAc-(1→2)-α-D-mannosyl-(1→3)-[β-D-GlcNAc-(1→2)-α-D-mannosyl-(1→6)]-β-D-mannosyl-(1→4)-β-D-GlcNAc-(1→4)-β-D-GlcNAc}-L-asparaginyl-[protein] 2-β-D-xylosyltransferase (configuration-inverting)
Comments: Specific for N-linked oligosaccharides (N-glycans).
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc, CAS registry number: 141256-56-6
References:
1.  Zeng, Y., Bannon, G., Thomas, V.H., Rice, K., Drake, R. and Elbein, A. Purification and specificity of β1,2-xylosyltransferase, an enzyme that contributes to the allergenicity of some plant proteins. J. Biol. Chem. 272 (1997) 31340–31347. [DOI] [PMID: 9395463]
2.  Strasser, R., Mucha, J., Mach, L., Altmann, F., Wilson, I.B., Glössl, J. and Steinkellner, H. Molecular cloning and functional expression of β1,2-xylosyltransferase cDNA from Arabidopsis thaliana. FEBS Lett. 472 (2000) 105–108. [DOI] [PMID: 10781814]
[EC 2.4.2.38 created 2001]
 
 
EC 2.4.1.267     Relevance: 84.1%
Accepted name: dolichyl-P-Glc:Man9GlcNAc2-PP-dolichol α-1,3-glucosyltransferase
Reaction: dolichyl β-D-glucosyl phosphate + α-D-Man-(1→2)-α-D-Man-(1→2)-α-D-Man-(1→3)-[α-D-Man-(1→2)-α-D-Man-(1→3)-[α-D-Man-(1→2)-α-D-Man-(1→6)]-α-D-Man-(1→6)]-β-D-Man-(1→4)-β-D-GlcNAc-(1→4)-α-D-GlcNAc-diphosphodolichol = α-D-Glc-(1→3)-α-D-Man-(1→2)-α-D-Man-(1→2)-α-D-Man-(1→3)-[α-D-Man-(1→2)-α-D-Man-(1→3)-[α-D-Man-(1→2)-α-D-Man-(1→6)]-α-D-Man-(1→6)]-β-D-Man-(1→4)-β-D-GlcNAc-(1→4)-α-D-GlcNAc-diphosphodolichol + dolichyl phosphate
For diagram of dolichyltetradecasaccharide biosynthesis, click here
Other name(s): ALG6; Dol-P-Glc:Man9GlcNAc2-PP-Dol α-1,3-glucosyltransferase; dolichyl β-D-glucosyl phosphate:D-Man-α-(1→2)-D-Man-α-(1→2)-D-Man-α-(1→3)-[D-Man-α-(1→2)-D-Man-α-(1→3)-[D-Man-α-(1→2)-D-Man-α-(1→6)]-D-Man-α-(1→6)]-D-Man-β-(1→4)-D-GlcNAc-β-(1→4)-D-GlcNAc-diphosphodolichol α-1,3-glucosyltransferase
Systematic name: dolichyl β-D-glucosyl-phosphate:α-D-Man-(1→2)-α-D-Man-(1→2)-α-D-Man-(1→3)-[α-D-Man-(1→2)-α-D-Man-(1→3)-[α-D-Man-(1→2)-α-D-Man-(1→6)]-α-D-Man-(1→6)]-β-D-Man-(1→4)-β-D-GlcNAc-(1→4)-α-D-GlcNAc-diphosphodolichol 3-α-D-glucosyltransferase (configuration-inverting)
Comments: The successive addition of three glucose residues by EC 2.4.1.267, EC 2.4.1.265 (Dol-P-Glc:Glc1Man9GlcNAc2-PP-Dol α-1,3-glucosyltransferase) and EC 2.4.1.256 (Dol-P-Glc:Glc2Man9GlcNAc2-PP-Dol α-1,2-glucosyltransferase) represents the final stage of the lipid-linked oligosaccharide assembly.
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc
References:
1.  Reiss, G., te Heesen, S., Zimmerman, J., Robbins, P.W. and Aebi, M. Isolation of the ALG6 locus of Saccharomyces cerevisiae required for glucosylation in the N-linked glycosylation pathway. Glycobiology 6 (1996) 493–498. [DOI] [PMID: 8877369]
2.  Runge, K.W., Huffaker, T.C. and Robbins, P.W. Two yeast mutations in glucosylation steps of the asparagine glycosylation pathway. J. Biol. Chem. 259 (1984) 412–417. [PMID: 6423630]
3.  Westphal, V., Xiao, M., Kwok, P.Y. and Freeze, H.H. Identification of a frequent variant in ALG6, the cause of congenital disorder of glycosylation-Ic. Hum. Mutat. 22 (2003) 420–421. [DOI] [PMID: 14517965]
[EC 2.4.1.267 created 2011, modified 2012]
 
 
EC 2.4.1.257     Relevance: 82.1%
Accepted name: GDP-Man:Man2GlcNAc2-PP-dolichol α-1,6-mannosyltransferase
Reaction: GDP-α-D-mannose + α-D-Man-(1→3)-β-D-Man-(1→4)-β-D-GlcNAc-(1→4)-α-D-GlcNAc-diphosphodolichol = GDP + α-D-Man-(1→3)-[α-D-Man-(1→6)]-β-D-Man-(1→4)-β-D-GlcNAc-(1→4)-α-D-GlcNAc-diphosphodolichol
For diagram of dolichyltetradecasaccharide biosynthesis, click here
Other name(s): GDP-Man:Man2GlcNAc2-PP-Dol α-1,6-mannosyltransferase; Alg2 mannosyltransferase (ambiguous); ALG2 (gene name, ambiguous); GDP-Man:Man1GlcNAc2-PP-dolichol mannosyltransferase (ambiguous); GDP-D-mannose:D-Man-α-(1→3)-D-Man-β-(1→4)-D-GlcNAc-β-(1→4)-D-GlcNAc-diphosphodolichol α-6-mannosyltransferase
Systematic name: GDP-α-D-mannose:α-D-Man-(1→3)-β-D-Man-(1→4)-β-D-GlcNAc-(1→4)-α-D-GlcNAc-diphosphodolichol 6-α-D-mannosyltransferase (configuration-retaining)
Comments: The biosynthesis of asparagine-linked glycoproteins utilizes a dolichyl diphosphate-linked glycosyl donor, which is assembled by the series of membrane-bound glycosyltransferases that comprise the dolichol pathway. Alg2 mannosyltransferase from Saccharomyces cerevisiae carries out an α1,3-mannosylation (cf. EC 2.4.1.132) of β-D-Man-(1→4)-β-D-GlcNAc-(1→4)-α-D-GlcNAc-diphosphodolichol, followed by an α1,6-mannosylation, to form the first branched pentasaccharide intermediate of the dolichol pathway [1,2].
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc
References:
1.  Kampf, M., Absmanner, B., Schwarz, M. and Lehle, L. Biochemical characterization and membrane topology of Alg2 from Saccharomyces cerevisiae as a bifunctional α1,3- and 1,6-mannosyltransferase involved in lipid-linked oligosaccharide biosynthesis. J. Biol. Chem. 284 (2009) 11900–11912. [DOI] [PMID: 19282279]
2.  O'Reilly, M.K., Zhang, G. and Imperiali, B. In vitro evidence for the dual function of Alg2 and Alg11: essential mannosyltransferases in N-linked glycoprotein biosynthesis. Biochemistry 45 (2006) 9593–9603. [DOI] [PMID: 16878994]
[EC 2.4.1.257 created 2011, modified 2012]
 
 
EC 2.4.1.265     Relevance: 81.7%
Accepted name: dolichyl-P-Glc:Glc1Man9GlcNAc2-PP-dolichol α-1,3-glucosyltransferase
Reaction: dolichyl β-D-glucosyl phosphate + α-D-Glc-(1→3)-α-D-Man-(1→2)-α-D-Man-(1→2)-α-D-Man-(1→3)-[α-D-Man-(1→2)-α-D-Man-(1→3)-[α-D-Man-(1→2)-α-D-Man-(1→6)]-α-D-Man-(1→6)]-β-D-Man-(1→4)-β-D-GlcNAc-(1→4)-α-D-GlcNAc-diphosphodolichol = α-D-Glc-(1→3)-α-D-Glc-(1→3)-α-D-Man-(1→2)-α-D-Man-(1→2)-α-D-Man-(1→3)-[α-D-Man-(1→2)-α-D-Man-(1→3)-[α-D-Man-(1→2)-α-D-Man-(1→6)]-α-D-Man-(1→6)]-β-D-Man-(1→4)-β-D-GlcNAc-(1→4)-α-D-GlcNAc-diphosphodolichol + dolichyl phosphate
For diagram of dolichyltetradecasaccharide biosynthesis, click here
Other name(s): ALG8; Dol-P-Glc:Glc1Man9GlcNAc2-PP-Dol α-1,3-glucosyltransferase; dolichyl β-D-glucosyl phosphate:D-Glc-α-(1→3)-D-Man-α-(1→2)-D-Man-α-(1→2)-D-Man-α-(1→3)-[D-Man-α-(1→2)-D-Man-α-(1→3)-[D-Man-α-(1→2)-D-Man-α-(1→6)]-D-Man-α-(1→6)]-D-Man-β-(1→4)-D-GlcNAc-β-(1→4)-D-GlcNAc-diphosphodolichol α-1,3-glucosyltransferase
Systematic name: dolichyl β-D-glucosyl-phosphate:α-D-Glc-(1→3)-α-D-Man-(1→2)-α-D-Man-(1→2)-α-D-Man-(1→3)-[α-D-Man-(1→2)-α-D-Man-(1→3)-[α-D-Man-(1→2)-α-D-Man-(1→6)]-α-D-Man-(1→6)]-β-D-Man-(1→4)-β-D-GlcNAc-(1→4)-α-D-GlcNAc-diphosphodolichol 3-α-D-glucosyltransferase (configuration-inverting)
Comments: The successive addition of three glucose residues by EC 2.4.1.267 (dolichyl-P-Glc:Man9GlcNAc2-PP-dolichol α-1,3-glucosyltransferase), EC 2.4.1.265 and EC 2.4.1.256 (dolichyl-P-Glc:Glc2Man9GlcNAc2-PP-dolichol α-1,2-glucosyltransferase) represents the final stage of the lipid-linked oligosaccharide assembly.
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc
References:
1.  Stagljar, I., te Heesen, S. and Aebi, M. New phenotype of mutations deficient in glucosylation of the lipid-linked oligosaccharide: cloning of the ALG8 locus. Proc. Natl. Acad. Sci. USA 91 (1994) 5977–5981. [DOI] [PMID: 8016100]
2.  Runge, K.W. and Robbins, P.W. A new yeast mutation in the glucosylation steps of the asparagine-linked glycosylation pathway. Formation of a novel asparagine-linked oligosaccharide containing two glucose residues. J. Biol. Chem. 261 (1986) 15582–15590. [PMID: 3536907]
3.  Chantret, I., Dancourt, J., Dupre, T., Delenda, C., Bucher, S., Vuillaumier-Barrot, S., Ogier de Baulny, H., Peletan, C., Danos, O., Seta, N., Durand, G., Oriol, R., Codogno, P. and Moore, S.E. A deficiency in dolichyl-P-glucose:Glc1Man9GlcNAc2-PP-dolichyl α3-glucosyltransferase defines a new subtype of congenital disorders of glycosylation. J. Biol. Chem. 278 (2003) 9962–9971. [DOI] [PMID: 12480927]
[EC 2.4.1.265 created 2011, modified 2012]
 
 
EC 2.4.1.163      
Transferred entry: β-galactosyl-N-acetylglucosaminylgalactosylglucosyl-ceramide β-1,3-acetylglucosaminyltransferase, now included in EC 2.4.1.149, N-acetyllactosaminide β-1,3-N-acetylglucosaminyltransferase
[EC 2.4.1.163 created 1989, deleted 2016]
 
 
EC 2.4.1.150     Relevance: 80.2%
Accepted name: N-acetyllactosaminide β-1,6-N-acetylglucosaminyltransferase
Reaction: UDP-N-acetyl-α-D-glucosamine + β-D-Gal-(1→4)-β-D-GlcNAc-(1→3)-β-D-Gal-(1→4)-β-D-GlcNAc-R = UDP + β-D-Gal-(1→4)-β-D-GlcNAc-(1→3)-[β-D-GlcNAc-(1→6)]-β-D-Gal-(1→4)-β-D-GlcNAc-R
Glossary: β-D-galactosyl-(1→4)-N-acetyl-D-glucosaminyl-R = type 2 precursor disaccharide
Other name(s): GCNT2 (gene name); GCNT3 (gene name); IGnT; I-branching β1,6-N-acetylglucosaminyltransferase; N-acetylglucosaminyltransferase; uridine diphosphoacetylglucosamine-acetyllactosaminide β1→6-acetylglucosaminyltransferase; Galβ1→4GlcNAc-R β1→6 N-acetylglucosaminyltransferase; UDP-N-acetyl-D-glucosamine:β-D-galactosyl-1,4-N-acetyl-D-glucosaminide β-1,6-N-acetyl-D-glucosaminyltransferase
Systematic name: UDP-N-acetyl-α-D-glucosamine:β-D-galactosyl-(1→4)-N-acetyl-β-D-glucosaminyl-(1→3)-β-D-galactosyl-(1→4)-N-acetyl-β-D-glucosaminide 6-β-N-acetylglucosaminyltransferase (configuration-inverting)
Comments: The enzyme acts on poly-N-acetyllactosamine [glycan chains of β-D-galactosyl-(1→4)-N-acetyl-D-glucosamine units connected by β(1,3) linkages] attached to proteins or lipids. It transfers a GlcNAc residue by β(1,6)-linkage to galactosyl residues close to non-reducing terminals, introducing a branching pattern known as I branching.
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc, CAS registry number: 85638-40-0
References:
1.  Van den Eijnden, D.H., Winterwerp, H., Smeeman, P. and Schiphorst, W.E.C.M. Novikoff ascites tumor cells contain N-acetyllactosaminide β1→3 and β1→6 N-acetylglucosaminyltransferase activity. J. Biol. Chem. 258 (1983) 3435–3437. [PMID: 6219989]
2.  Basu, M. and Basu, S. Biosynthesis in vitro of Ii core glycosphingolipids from neolactotetraosylceramide by β 1-3- and β 1-6-N-acetylglucosaminyltransferases from mouse T-lymphoma. J. Biol. Chem. 259 (1984) 12557–12562. [PMID: 6238026]
3.  Piller, F., Cartron, J.P., Maranduba, A., Veyrieres, A., Leroy, Y. and Fournet, B. Biosynthesis of blood group I antigens. Identification of a UDP-GlcNAc:GlcNAc β1-3Gal(-R) β1-6(GlcNAc to Gal) N-acetylglucosaminyltransferase in hog gastric mucosa. J. Biol. Chem. 259 (1984) 13385–13390. [PMID: 6490658]
4.  Bierhuizen, M.F., Maemura, K., Kudo, S. and Fukuda, M. Genomic organization of core 2 and I branching β-1,6-N-acetylglucosaminyltransferases. Implication for evolution of the β-1,6-N-acetylglucosaminyltransferase gene family. Glycobiology 5 (1995) 417–425. [DOI] [PMID: 7579796]
5.  Ujita, M., McAuliffe, J., Suzuki, M., Hindsgaul, O., Clausen, H., Fukuda, M.N. and Fukuda, M. Regulation of I-branched poly-N-acetyllactosamine synthesis. Concerted actions by I-extension enzyme, I-branching enzyme, and β1,4-galactosyltransferase I. J. Biol. Chem. 274 (1999) 9296–9304. [DOI] [PMID: 10092606]
6.  Yeh, J.C., Ong, E. and Fukuda, M. Molecular cloning and expression of a novel β-1,6-N-acetylglucosaminyltransferase that forms core 2, core 4, and I branches. J. Biol. Chem. 274 (1999) 3215–3221. [DOI] [PMID: 9915862]
[EC 2.4.1.150 created 1984 (EC 2.4.1.164 created 1989, incorporated 2016), modified 2017]
 
 
EC 2.4.1.143     Relevance: 79.9%
Accepted name: α-1,6-mannosyl-glycoprotein 2-β-N-acetylglucosaminyltransferase
Reaction: UDP-N-acetyl-α-D-glucosamine + β-D-GlcNAc-(1→2)-α-D-Man-(1→3)-[α-D-Man-(1→6)]-β-D-Man-(1→4)-β-D-GlcNAc-(1→4)-β-D-GlcNAc-N-Asn-[protein] = UDP + β-D-GlcNAc-(1→2)-α-D-Man-(1→3)-[β-D-GlcNAc-(1→2)-α-D-Man-(1→6)]-β-D-Man-(1→4)-β-D-GlcNAc-(1→4)-β-D-GlcNAc-N-Asn-[protein]
For diagram of mannosyl-glycoprotein N-acetylglucosaminyltransferases, click here
Other name(s): MGAT2 (gene name); N-acetylglucosaminyltransferase II; N-glycosyl-oligosaccharide-glycoprotein N-acetylglucosaminyltransferase II; acetylglucosaminyltransferase II; uridine diphosphoacetylglucosamine-mannoside α1→6-acetylglucosaminyltransferase; uridine diphosphoacetylglucosamine-α-1,6-mannosylglycoprotein β-1-2-N-acetylglucosaminyltransferase; uridine diphosphoacetylglucosamine-α-D-mannoside β1-2-acetylglucosaminyltransferase; UDP-GlcNAc:mannoside α1-6 acetylglucosaminyltransferase; α-1,6-mannosyl-glycoprotein β-1,2-N-acetylglucosaminyltransferase; GnTII; GlcNAc-T II; UDP-N-acetyl-D-glucosamine:6-(α-D-mannosyl)-β-D-mannosyl-glycoprotein 2-β-N-acetyl-D-glucosaminyltransferase
Systematic name: UDP-N-acetyl-α-D-glucosamine:α-D-mannosyl-(1→6)-β-D-mannosyl-glycoprotein 2-β-N-acetyl-D-glucosaminyltransferase (configuration-inverting)
Comments: The enzyme, found in plants and animals, participates in the processing of N-glycans in the Golgi apparatus. Its activity initiates the synthesis of the second antenna of di-antennary complex N-glycans. While the natural substrate (produced by EC 3.2.1.114, mannosyl-oligosaccharide 1,3-1,6-α-mannosidase) is described here, the minimal substrate recognized by the enzyme is α-D-Man-(1→6)-[β-D-GlcNAc-(1→2)-α-D-Man-(1→3)]-β-D-Man-R.
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc, CAS registry number: 105913-04-0
References:
1.  Harpaz, N. and Schachter, H. Control of glycoprotein synthesis. Bovine colostrum UDP-N-acetylglucosamine:α-D-mannoside β2-N-acetylglucosaminyltransferase I. Separation from UDP-N-acetylglucosamine:α-D-mannoside β2-N-acetylglucosaminyltransferase II, partial purification, and substrate specificity. J. Biol. Chem. 255 (1980) 4885–4893. [PMID: 6445358]
2.  Mendicino, J., Chandrasekaran, E.V., Anumula, K.R. and Davila, M. Isolation and properties of α-D-mannose:β-1,2-N-acetylglucosaminyltransferase from trachea mucosa. Biochemistry 20 (1981) 967–976. [PMID: 6452163]
3.  Oppenheimer, C.L., Eckhardt, A.E. and Hill, R.L. The nonidentity of porcine N-acetylglucosaminyltransferases I and II. J. Biol. Chem. 256 (1981) 11477–11482. [PMID: 6457827]
4.  Schachter, H., Narasimhan, S., Gleeson, P. and Vella, G. Glycosyltransferases involved in elongation of N-glycosidically linked oligosaccharides of the complex or N-acetyllactosamine type. Methods Enzymol. 98 (1983) 98–134. [PMID: 6366476]
5.  Bendiak, B. and Schachter, H. Control of glycoprotein synthesis. Kinetic mechanism, substrate specificity, and inhibition characteristics of UDP-N-acetylglucosamine:α-D-mannoside β-1-2 N-acetylglucosaminyltransferase II from rat liver. J. Biol. Chem. 262 (1987) 5784–5790. [PMID: 2952645]
6.  Bendiak, B. and Schacter, H. Control of glycoprotein synthesis. Purification of UDP-N-acetylglucosamine:α-D-mannoside β1-2 N-acetylglucosaminyltransferase II from rat liver. J. Biol. Chem. 262 (1987) 5775–5783. [PMID: 2952644]
7.  Tan, J., D'Agostaro, A.F., Bendiak, B., Reck, F., Sarkar, M., Squire, J.A., Leong, P. and Schachter, H. The human UDP-N-acetylglucosamine: α-6-D-mannoside-β-1,2- N-acetylglucosaminyltransferase II gene (MGAT2). Cloning of genomic DNA, localization to chromosome 14q21, expression in insect cells and purification of the recombinant protein. Eur. J. Biochem. 231 (1995) 317–328. [DOI] [PMID: 7635144]
[EC 2.4.1.143 created 1984, modified 2001 (EC 2.4.1.51 created 1972, part incorporated 1984), modified 2018]
 
 
EC 2.4.1.260     Relevance: 78.9%
Accepted name: dolichyl-P-Man:Man7GlcNAc2-PP-dolichol α-1,6-mannosyltransferase
Reaction: dolichyl β-D-mannosyl phosphate + α-D-Man-(1→2)-α-D-Man-(1→2)-α-D-Man-(1→3)-[α-D-Man-(1→2)-α-D-Man-(1→3)-α-D-Man-(1→6)]-β-D-Man-β-(1→4)-β-D-GlcNAc-(1→4)-α-D-GlcNAc-diphosphodolichol = α-D-Man-α-(1→2)-α-D-Man-(1→2)-α-D-Man-(1→3)-[α-D-Man-(1→2)-α-D-Man-(1→3)-[α-D-Man-(1→6)]-α-D-Man-(1→6)]-β-D-Man-(1→4)-β-D-GlcNAc-(1→4)-α-D-GlcNAc-diphosphodolichol + dolichyl phosphate
For diagram of dolichyltetradecasaccharide biosynthesis, click here
Other name(s): ALG12; ALG12 mannosyltransferase; ALG12 α1,6mannosyltransferase; dolichyl-P-mannose:Man7GlcNAc2-PP-dolichyl mannosyltransferase; dolichyl-P-Man:Man7GlcNAc2-PP-dolichyl α6-mannosyltransferase; EBS4; Dol-P-Man:Man7GlcNAc2-PP-Dol α-1,6-mannosyltransferase; dolichyl β-D-mannosyl phosphate:D-Man-α-(1→2)-D-Man-α-(1→2)-D-Man-α-(1→3)-[D-Man-α-(1→2)-D-Man-α-(1→3)-D-Man-α-(1→6)]-D-Man-β-(1→4)-D-GlcNAc-β-(1→4)-D-GlcNAc-diphosphodolichol α-1,6-mannosyltransferase
Systematic name: dolichyl β-D-mannosyl-phosphate:α-D-Man-(1→2)-α-D-Man-(1→2)-α-D-Man-(1→3)-[α-D-Man-(1→2)-α-D-Man-(1→3)-α-D-Man-(1→6)]-β-D-Man-β-(1→4)-β-D-GlcNAc-(1→4)-α-D-GlcNAc-diphosphodolichol 6-α-D-mannosyltransferase (configuration-inverting)
Comments: The formation of N-glycosidic linkages of glycoproteins involves the ordered assembly of the common Glc3Man9GlcNAc2 core-oligosaccharide on the lipid carrier dolichyl diphosphate. Early mannosylation steps occur on the cytoplasmic side of the endoplasmic reticulum with GDP-Man as donor, the final reactions from Man5GlcNAc2-PP-Dol to Man9Glc-NAc2-PP-Dol on the lumenal side use dolichyl β-D-mannosyl phosphate.
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc
References:
1.  Frank, C.G. and Aebi, M. ALG9 mannosyltransferase is involved in two different steps of lipid-linked oligosaccharide biosynthesis. Glycobiology 15 (2005) 1156–1163. [DOI] [PMID: 15987956]
2.  Hong, Z., Jin, H., Fitchette, A.C., Xia, Y., Monk, A.M., Faye, L. and Li, J. Mutations of an α1,6 mannosyltransferase inhibit endoplasmic reticulum-associated degradation of defective brassinosteroid receptors in Arabidopsis. Plant Cell 21 (2009) 3792–3802. [DOI] [PMID: 20023196]
3.  Cipollo, J.F. and Trimble, R.B. The Saccharomyces cerevisiae alg12δ mutant reveals a role for the middle-arm α1,2Man- and upper-arm α1,2Manα1,6Man- residues of Glc3Man9GlcNAc2-PP-Dol in regulating glycoprotein glycan processing in the endoplasmic reticulum and Golgi apparatus. Glycobiology 12 (2002) 749–762. [PMID: 12460943]
4.  Grubenmann, C.E., Frank, C.G., Kjaergaard, S., Berger, E.G., Aebi, M. and Hennet, T. ALG12 mannosyltransferase defect in congenital disorder of glycosylation type lg. Hum. Mol. Genet. 11 (2002) 2331–2339. [DOI] [PMID: 12217961]
[EC 2.4.1.260 created 1976 as EC 2.4.1.130, part transferred 2011 to EC 2.4.1.160, modified 2012]
 
 
EC 2.4.1.68     Relevance: 78.8%
Accepted name: glycoprotein 6-α-L-fucosyltransferase
Reaction: GDP-β-L-fucose + N4-{β-D-GlcNAc-(1→2)-α-D-Man-(1→3)-[β-D-GlcNAc-(1→2)-α-D-Man-(1→6)]-β-D-Man-(1→4)-β-D-GlcNAc-(1→4)-β-D-GlcNAc}-L-asparaginyl-[protein] = GDP + N4-{β-D-GlcNAc-(1→2)-α-D-Man-(1→3)-[β-D-GlcNAc-(1→2)-α-D-Man-(1→6)]-β-D-Man-(1→4)-β-D-GlcNAc-(1→4)-[α-L-Fuc-(1→6)]-β-D-GlcNAc}-L-asparaginyl-[protein]
For diagram of mannosyl-glycoprotein fucosyl and xylosyl transferases, click here
Other name(s): GDP-fucose—glycoprotein fucosyltransferase; GDP-L-Fuc:N-acetyl-β-D-glucosaminide α1→6fucosyltransferase; GDP-L-fucose-glycoprotein fucosyltransferase; glycoprotein fucosyltransferase; guanosine diphosphofucose-glycoprotein fucosyltransferase; GDP-L-fucose:glycoprotein (L-fucose to asparagine-linked N-acetylglucosamine of 4-N-{N-acetyl-β-D-glucosaminyl-(1→2)-α-D-mannosyl-(1→3)-[N-acetyl-β-D-glucosaminyl-(1→2)-α-D-mannosyl-(1→6)]-β-D-mannosyl-(1→4)-N-acetyl-β-D-glucosaminyl-(1→4)-N-acetyl-β-D-glucosaminyl}asparagine) 6-α-L-fucosyltransferase; FucT; GDP-L-fucose:glycoprotein (L-fucose to asparagine-linked N-acetylglucosamine of N4-{N-acetyl-β-D-glucosaminyl-(1→2)-α-D-mannosyl-(1→3)-[N-acetyl-β-D-glucosaminyl-(1→2)-α-D-mannosyl-(1→6)]-β-D-mannosyl-(1→4)-N-acetyl-β-D-glucosaminyl-(1→4)-N-acetyl-β-D-glucosaminyl}asparagine) 6-α-L-fucosyltransferase; GDP-β-L-fucose:glycoprotein (L-fucose to asparagine-linked N-acetylglucosamine of N4-{N-acetyl-β-D-glucosaminyl-(1→2)-α-D-mannosyl-(1→3)-[N-acetyl-β-D-glucosaminyl-(1→2)-α-D-mannosyl-(1→6)]-β-D-mannosyl-(1→4)-N-acetyl-β-D-glucosaminyl-(1→4)-N-acetyl-β-D-glucosaminyl}asparagine) 6-α-L-fucosyltransferase
Systematic name: GDP-β-L-fucose:N4-{β-D-GlcNAc-(1→2)-α-D-Man-(1→3)-[β-D-GlcNAc-(1→2)-α-D-Man-(1→6)]-β-D-Man-(1→4)-β-D-GlcNAc-(1→4)-β-D-GlcNAc}-L-asparaginyl-[protein] 6-α-L-fucosyltransferase (configuration-inverting)
Comments: This enzyme catalyses a reaction similar to that of EC 2.4.1.214, glycoprotein 3-α-L-fucosyltransferase, but transfers the L-fucosyl group from GDP-β-L-fucose to form an α1,6-linkage rather than an α1,3-linkage.
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc, PDB, CAS registry number: 9033-08-3
References:
1.  Longmore, G.D. and Schachter, H. Product-identification and substrate-specificity studies of the GDP-L-fucose:2-acetamido-2-deoxy-β-D-glucoside (Fuc → Asn-linked GlcNAc) 6-α-L-fucosyltransferase in a Golgi-rich fraction from porcine liver. Carbohydr. Res. 100 (1982) 365–392. [DOI] [PMID: 7083256]
2.  Voynow, J.A., Scanlin, T.F. and Glick, M.C. A quantitative method for GDP-L-Fuc:N-acetyl-β-D-glucosaminide α1→6fucosyltransferase activity with lectin affinity chromatography. Anal. Biochem. 168 (1988) 367–373. [DOI] [PMID: 3364733]
3.  Uozumi, N., Yanagidani, S., Miyoshi, E., Ihara, Y., Sakuma, T., Gao, C.-X., Teshima, T., Fujii, S., Shiba, T. and Taniguchi, N. Purification and cDNA cloning of porcine brain GDP-L-Fuc:N-acetyl-β-D-glucosaminide α1→6fucosyltransferase. J. Biol. Chem. 271 (1996) 27810–27817. [DOI] [PMID: 8910378]
[EC 2.4.1.68 created 1972, modified 2002]
 
 
EC 2.4.1.256     Relevance: 78.8%
Accepted name: dolichyl-P-Glc:Glc2Man9GlcNAc2-PP-dolichol α-1,2-glucosyltransferase
Reaction: dolichyl β-D-glucosyl phosphate + α-D-Glc-(1→3)-α-D-Glc-(1→3)-α-D-Man-(1→2)-α-D-Man-(1→2)-α-D-Man-(1→3)-[α-D-Man-(1→2)-α-D-Man-(1→3)-[α-D-Man-(1→2)-α-D-Man-(1→6)]-α-D-Man-(1→6)]-β-D-Man-(1→4)-β-D-GlcNAc-(1→4)-α-D-GlcNAc-diphosphodolichol = dolichyl phosphate + α-D-Glc-(1→2)-α-D-Glc-(1→3)-α-D-Glc-(1→3)-α-D-Man-(1→2)-α-D-Man-(1→2)-α-D-Man-(1→3)-[α-D-Man-(1→2)-α-D-Man-(1→3)-[α-D-Man-(1→2)-α-D-Man-(1→6)]-α-D-Man-(1→6)]-β-D-Man-(1→4)-β-D-GlcNAc-(1→4)-α-D-GlcNAc-diphosphodolichol
For diagram of dolichyltetradecasaccharide biosynthesis, click here
Other name(s): ALG10; Dol-P-Glc:Glc2Man9GlcNAc2-PP-Dol α-1,2-glucosyltransferase; dolichyl β-D-glucosyl phosphate:D-Glc-α-(1→3)-D-Glc-α-(1→3)-D-Man-α-(1→2)-D-Man-α-(1→2)-D-Man-α-(1→3)-[D-Man-α-(1→2)-D-Man-α-(1→3)-[D-Man-α-(1→2)-D-Man-α-(1→6)]-D-Man-α-(1→6)]-D-Man-β-(1→4)-D-GlcNAc-β-(1→4)-D-GlcNAc-diphosphodolichol 2-α-D-glucosyltransferase
Systematic name: dolichyl β-D-glucosyl-phosphate:α-D-Glc-(1→3)-α-D-Glc-(1→3)-α-D-Man-(1→2)-α-D-Man-(1→2)-α-D-Man-(1→3)-[α-D-Man-(1→2)-α-D-Man-(1→3)-[α-D-Man-(1→2)-α-D-Man-(1→6)]-α-D-Man-(1→6)]-β-D-Man-(1→4)-β-D-GlcNAc-(1→4)-α-D-GlcNAc-diphosphodolichol α-1,2-glucosyltransferase (configuration-retaining)
Comments: This eukaryotic enzyme performs the final step in the synthesis of the lipid-linked oligosaccharide, attaching D-glucose in an α-1,2-linkage to the outermost D-glucose in the long branch. The lipid-linked oligosaccharide is involved in N-linked protein glycosylation of selected asparagine residues of nascent polypeptide chains in eukaryotic cells.
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc
References:
1.  Burda, P. and Aebi, M. The ALG10 locus of Saccharomyces cerevisiae encodes the α-1,2 glucosyltransferase of the endoplasmic reticulum: the terminal glucose of the lipid-linked oligosaccharide is required for efficient N-linked glycosylation. Glycobiology 8 (1998) 455–462. [DOI] [PMID: 9597543]
[EC 2.4.1.256 created 2011, modified 2012]
 
 
EC 2.4.1.214     Relevance: 78.3%
Accepted name: glycoprotein 3-α-L-fucosyltransferase
Reaction: GDP-β-L-fucose + N4-{β-D-GlcNAc-(1→2)-α-D-Man-(1→3)-[β-D-GlcNAc-(1→2)-α-D-Man-(1→6)]-β-D-Man-(1→4)-β-D-GlcNAc-(1→4)-β-D-GlcNAc}-L-asparaginyl-[protein] = GDP + N4-{β-D-GlcNAc-(1→2)-α-D-Man-(1→3)-[β-D-GlcNAc-(1→2)-α-D-Man-(1→6)]-β-D-Man-(1→4)-β-D-GlcNAc-(1→4)-[α-L-Fuc-(1→3)]-β-D-GlcNAc}-L-asparaginyl-[protein]
For diagram of mannosyl-glycoprotein fucosyl and xylosyl transferases, click here
Other name(s): GDP-L-Fuc:N-acetyl-β-D-glucosaminide α1,3-fucosyltransferase; GDP-L-Fuc:Asn-linked GlcNAc α1,3-fucosyltransferase; GDP-fucose:β-N-acetylglucosamine (Fuc to (Fucα1→6GlcNAc)-Asn-peptide) α1→3-fucosyltransferase; GDP-L-fucose:glycoprotein (L-fucose to asparagine-linked N-acetylglucosamine of 4-N-{N-acetyl-β-D-glucosaminyl-(1→2)-α-D-mannosyl-(1→3)-[N-acetyl-β-D-glucosaminyl-(1→2)-α-D-mannosyl-(1→6)]-β-D-mannosyl-(1→4)-N-acetyl-β-D-glucosaminyl-(1→4)-N-acetyl-β-D-glucosaminyl}asparagine) 3-α-L-fucosyl-transferase; GDP-L-fucose:glycoprotein (L-fucose to asparagine-linked N-acetylglucosamine of N4-{N-acetyl-β-D-glucosaminyl-(1→2)-α-D-mannosyl-(1→3)-[N-acetyl-β-D-glucosaminyl-(1→2)-α-D-mannosyl-(1→6)]-β-D-mannosyl-(1→4)-N-acetyl-β-D-glucosaminyl-(1→4)-N-acetyl-β-D-glucosaminyl}asparagine) 3-α-L-fucosyl-transferase; GDP-β-L-fucose:glycoprotein (L-fucose to asparagine-linked N-acetylglucosamine of N4-{N-acetyl-β-D-glucosaminyl-(1→2)-α-D-mannosyl-(1→3)-[N-acetyl-β-D-glucosaminyl-(1→2)-α-D-mannosyl-(1→6)]-β-D-mannosyl-(1→4)-N-acetyl-β-D-glucosaminyl-(1→4)-N-acetyl-β-D-glucosaminyl}asparagine) 3-α-L-fucosyl-transferase
Systematic name: GDP-β-L-fucose:N4-{β-D-GlcNAc-(1→2)-α-D-Man-(1→3)-[β-D-GlcNAc-(1→2)-α-D-Man-(1→6)]-β-D-Man-(1→4)-β-D-GlcNAc-(1→4)-β-D-GlcNAc}-L-asparaginyl-[protein] 3-α-L-fucosyltransferase (configuration-retaining)
Comments: Requires Mn2+. The enzyme transfers to N-linked oligosaccharide structures (N-glycans), generally with a specificity for N-glycans with one unsubstituted non-reducing terminal GlcNAc residue. This enzyme catalyses a reaction similar to that of EC 2.4.1.68, glycoprotein 6-α-L-fucosyltransferase, but transferring the L-fucosyl group from GDP-β-L-fucose to form an α1,3-linkage rather than an α1,6-linkage. The N-glycan products of this enzyme are present in plants, insects and some other invertebrates (e.g., Schistosoma, Haemonchus, Lymnaea).
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc, CAS registry number: 68247-53-0
References:
1.  Wilson, I.B.H., Rendic, D., Freilinger, A., Dumic, J., Altmann, F., Mucha, J., Müller, S. and Hauser, M.-T. Cloning and expression of α1,3-fucosyltransferase homologues from Arabidopsis thaliana. Biochim. Biophys. Acta 1527 (2001) 88–96. [DOI] [PMID: 11420147]
2.  Fabini, G., Freilinger, A., Altmann, F. and Wilson, I.B.H. Identification of core α1,3-fucosylated glycans and cloning of the requisite fucosyltransferase cDNA from Drosophila melanogaster. Potential basis of the neural anti-horseradish peroxidase epitope. J. Biol. Chem. 276 (2001) 28058–28067. [DOI] [PMID: 11382750]
3.  Leiter, H., Mucha, J., Staudacher, E., Grimm, R., Glössl, J. and Altmann, F. Purification, cDNA cloning, and expression of GDP-L-Fuc:Asn-linked GlcNAc α1,3-fucosyltransferase from mung beans. J. Biol. Chem. 274 (1999) 21830–21839. [DOI] [PMID: 10419500]
4.  van Tetering, A., Schiphorst, W.E.C.M., van den Eijnden, D.H. and van Die, I. Characterization of core α1→3-fucosyltransferase from the snail Lymnaea stagnalis that is involved in the synthesis of complex type N-glycans. FEBS Lett. 461 (1999) 311–314. [DOI] [PMID: 10567717]
5.  Staudacher, E., Altmann, F., Glössl, J., März, L., Schachter, H., Kamerling, J.P., Haard, K. and Vliegenthart, J.F.G. GDP-fucose:β-N-acetylglucosamine (Fuc to (Fucα1→6GlcNAc)-Asn-peptide) α1→3-fucosyltransferase activity in honeybee (Apis mellifica) venom glands. The difucosylation of asparagine-bound N-acetylglucosamine. Eur. J. Biochem. 199 (1991) 745–751. [DOI] [PMID: 1868856]
[EC 2.4.1.214 created 2001]
 
 
EC 3.2.1.207     Relevance: 76.9%
Accepted name: mannosyl-oligosaccharide α-1,3-glucosidase
Reaction: (1) Glc2Man9GlcNAc2-[protein] + H2O = GlcMan9GlcNAc2-[protein] + β-D-glucopyranose
(2) GlcMan9GlcNAc2-[protein] + H2O = Man9GlcNAc2-[protein] + β-D-glucopyranose
Glossary: Glc2Man9GlcNAc2-[protein] = {α-D-Glc-(1→3)-α-D-Glc-(1→3)-α-D-Man-(1→2)-α-D-Man-(1→2)-α-D-Man-(1→3)-[α-D-Man-(1→2)-α-D-Man-(1→3)-[α-D-Man-(1→2)-α-D-Man-(1→6)]-α-D-Man-(1→6)]-β-D-Man-(1→4)-β-D-GlcNAc-(1→4)-β-D-GlcNAc}-N-Asn-[protein]
GlcMan9GlcNAc2-[protein] = {α-D-Glc-(1→3)-α-D-Man-(1→2)-α-D-Man-(1→2)-α-D-Man-(1→3)-[α-D-Man-(1→2)-α-D-Man-(1→3)-[α-D-Man-(1→2)-α-D-Man-(1→6)]-α-D-Man-(1→6)]-β-D-Man-(1→4)-β-D-GlcNAc-(1→4)-β-D-GlcNAc}-N-Asn-[protein]
Man9GlcNAc2-[protein] = {α-D-Man-(1→2)-α-D-Man-(1→2)-α-D-Man-(1→3)-[α-D-Man-(1→2)-α-D-Man-(1→3)-[α-D-Man-(1→2)-α-D-Man-(1→6)]-α-D-Man-(1→6)]-β-D-Man-(1→4)-β-D-GlcNAc-(1→4)-β-D-GlcNAc}-N-Asn-[protein]
Other name(s): ER glucosidase II; α-glucosidase II; trimming glucosidase II; ROT2 (gene name); GTB1 (gene name); GANAB (gene name); PRKCSH (gene name)
Systematic name: Glc2Man9GlcNAc2-[protein] 3-α-glucohydrolase (configuration-inverting)
Comments: This eukaryotic enzyme cleaves off sequentially the two α-1,3-linked glucose residues from the Glc2Man9GlcNAc2 oligosaccharide precursor of immature N-glycosylated proteins.
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc
References:
1.  Trombetta, E.S., Simons, J.F. and Helenius, A. Endoplasmic reticulum glucosidase II is composed of a catalytic subunit, conserved from yeast to mammals, and a tightly bound noncatalytic HDEL-containing subunit. J. Biol. Chem. 271 (1996) 27509–27516. [DOI] [PMID: 8910335]
2.  Ziak, M., Meier, M., Etter, K.S. and Roth, J. Two isoforms of trimming glucosidase II exist in mammalian tissues and cell lines but not in yeast and insect cells. Biochem. Biophys. Res. Commun. 280 (2001) 363–367. [DOI] [PMID: 11162524]
3.  Wilkinson, B.M., Purswani, J. and Stirling, C.J. Yeast GTB1 encodes a subunit of glucosidase II required for glycoprotein processing in the endoplasmic reticulum. J. Biol. Chem. 281 (2006) 6325–6333. [DOI] [PMID: 16373354]
4.  Mora-Montes, H.M., Bates, S., Netea, M.G., Diaz-Jimenez, D.F., Lopez-Romero, E., Zinker, S., Ponce-Noyola, P., Kullberg, B.J., Brown, A.J., Odds, F.C., Flores-Carreon, A. and Gow, N.A. Endoplasmic reticulum α-glycosidases of Candida albicans are required for N glycosylation, cell wall integrity, and normal host-fungus interaction. Eukaryot Cell 6 (2007) 2184–2193. [DOI] [PMID: 17933909]
[EC 3.2.1.207 created 2018]
 
 
EC 2.4.1.164      
Transferred entry: galactosyl-N-acetylglucosaminylgalactosylglucosyl-ceramide β-1,6-N-acetylglucosaminyltransferase, now included with EC 2.4.1.150, N-acetyllactosaminide β-1,6-N-acetylglucosaminyltransferase
[EC 2.4.1.164 created 1989, deleted 2016]
 
 
EC 2.4.1.258     Relevance: 76.5%
Accepted name: dolichyl-P-Man:Man5GlcNAc2-PP-dolichol α-1,3-mannosyltransferase
Reaction: dolichyl β-D-mannosyl phosphate + α-D-Man-(1→2)-α-D-Man-(1→2)-α-D-Man-(1→3)-[α-D-Man-(1→6)]-β-D-Man-(1→4)-β-D-GlcNAc-(1→4)-α-D-GlcNAc-diphosphodolichol = α-D-Man-(1→2)-α-D-Man-(1→2)-α-D-Man-(1→3)-[α-D-Man-(1→3)-α-D-Man-(1→6)]-β-D-Man-(1→4)-β-D-GlcNAc-(1→4)-α-D-GlcNAc-diphosphodolichol + dolichyl phosphate
For diagram of dolichyltetradecasaccharide biosynthesis, click here
Other name(s): Man5GlcNAc2-PP-Dol mannosyltransferase; ALG3; dolichyl-P-Man:Man(5)GlcNAc(2)-PP-dolichyl mannosyltransferase; Not56-like protein; Alg3 α-1,3-mannosyl transferase; Dol-P-Man:Man5GlcNAc2-PP-Dol α-1,3-mannosyltransferase; dolichyl β-D-mannosyl phosphate:D-Man-α-(1→2)-D-Man-α-(1→2)-D-Man-α-(1→3)-[D-Man-α-(1→6)]-D-Man-β-(1→4)-D-GlcNAc-β-(1→4)-D-GlcNAc-diphosphodolichol α-1,3-mannosyltransferase
Systematic name: dolichyl β-D-mannosyl-phosphate:α-D-Man-(1→2)-α-D-Man-(1→2)-α-D-Man-(1→3)-[α-D-Man-(1→6)]-β-D-Man-(1→4)-β-D-GlcNAc-(1→4)-α-D-GlcNAc-diphosphodolichol 3-α-D-mannosyltransferase (configuration-inverting)
Comments: The formation of N-glycosidic linkages of glycoproteins involves the ordered assembly of the common Glc3Man9GlcNAc2 core-oligosaccharide on the lipid carrier dolichyl diphosphate. Early mannosylation steps occur on the cytoplasmic side of the endoplasmic reticulum with GDP-Man as donor, the final reactions from Man5GlcNAc2-PP-dolichol to Man9Glc-NAc2-PP-dolichol on the lumenal side use dolichyl β-D-mannosyl phosphate. The first step of this assembly pathway on the luminal side of the endoplasmic reticulum is catalysed by ALG3.
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc
References:
1.  Sharma, C.B., Knauer, R. and Lehle, L. Biosynthesis of lipid-linked oligosaccharides in yeast: the ALG3 gene encodes the Dol-P-Man:Man5GlcNAc2-PP-Dol mannosyltransferase. Biol. Chem. 382 (2001) 321–328. [DOI] [PMID: 11308030]
2.  Cipollo, J.F. and Trimble, R.B. The accumulation of Man(6)GlcNAc(2)-PP-dolichol in the Saccharomyces cerevisiae Δalg9 mutant reveals a regulatory role for the Alg3p α1,3-Man middle-arm addition in downstream oligosaccharide-lipid and glycoprotein glycan processing. J. Biol. Chem. 275 (2000) 4267–4277. [DOI] [PMID: 10660594]
[EC 2.4.1.258 created 1976 as EC 2.4.1.130, part transferred 2011 to EC 2.4.1.258, modified 2012]
 
 
EC 2.4.1.259     Relevance: 75.4%
Accepted name: dolichyl-P-Man:Man6GlcNAc2-PP-dolichol α-1,2-mannosyltransferase
Reaction: dolichyl β-D-mannosyl phosphate + α-D-Man-(1→2)-α-D-Man-(1→2)-α-D-Man-(1→3)-[α-D-Man-(1→3)-α-D-Man-(1→6)]-β-D-Man-(1→4)-β-D-GlcNAc-(1→4)-α-D-GlcNAc-diphosphodolichol = α-D-Man-(1→2)-α-D-Man-(1→2)-α-D-Man-(1→3)-[α-D-Man-(1→2)-α-D-Man-(1→3)-α-D-Man-(1→6)]-β-D-Man-(1→4)-β-D-GlcNAc-(1→4)-α-D-GlcNAc-diphosphodolichol + dolichyl phosphate
For diagram of dolichyltetradecasaccharide biosynthesis, click here
Other name(s): ALG9; ALG9 α1,2 mannosyltransferase; dolichylphosphomannose-dependent ALG9 mannosyltransferase; ALG9 mannosyltransferase; Dol-P-Man:Man6GlcNAc2-PP-Dol α-1,2-mannosyltransferase; dolichyl β-D-mannosyl phosphate:D-Man-α-(1→2)-D-Man-α-(1→2)-D-Man-α-(1→3)-[D-Man-α-(1→3)-D-Man-α-(1→6)]-D-Man-β-(1→4)-D-GlcNAc-β-(1→4)-D-GlcNAc-diphosphodolichol α-1,2-mannosyltransferase
Systematic name: dolichyl β-D-mannosyl-phosphate:α-D-Man-(1→2)-α-D-Man-(1→2)-α-D-Man-(1→3)-[α-D-Man-(1→3)-α-D-Man-(1→6)]-β-D-Man-(1→4)-β-D-GlcNAc-(1→4)-α-D-GlcNAc-diphosphodolichol 2-α-D-mannosyltransferase (configuration-inverting)
Comments: The formation of N-glycosidic linkages of glycoproteins involves the ordered assembly of the common Glc3Man9GlcNAc2 core-oligosaccharide on the lipid carrier dolichyl diphosphate. Early mannosylation steps occur on the cytoplasmic side of the endoplasmic reticulum with GDP-Man as donor, the final reactions from Man5GlcNAc2-PP-Dol to Man9Glc-NAc2-PP-Dol on the lumenal side use dolichyl β-D-mannosyl phosphate. ALG9 mannosyltransferase catalyses the addition of two different α-1,2-mannose residues - the addition of α-1,2-mannose to Man6GlcNAc2-PP-Dol (EC 2.4.1.259) and the addition of α-1,2-mannose to Man8GlcNAc2-PP-Dol (EC 2.4.1.261).
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc
References:
1.  Vleugels, W., Keldermans, L., Jaeken, J., Butters, T.D., Michalski, J.C., Matthijs, G. and Foulquier, F. Quality control of glycoproteins bearing truncated glycans in an ALG9-defective (CDG-IL) patient. Glycobiology 19 (2009) 910–917. [DOI] [PMID: 19451548]
2.  Cipollo, J.F. and Trimble, R.B. The accumulation of Man(6)GlcNAc(2)-PP-dolichol in the Saccharomyces cerevisiae Δalg9 mutant reveals a regulatory role for the Alg3p α1,3-Man middle-arm addition in downstream oligosaccharide-lipid and glycoprotein glycan processing. J. Biol. Chem. 275 (2000) 4267–4277. [DOI] [PMID: 10660594]
3.  Frank, C.G. and Aebi, M. ALG9 mannosyltransferase is involved in two different steps of lipid-linked oligosaccharide biosynthesis. Glycobiology 15 (2005) 1156–1163. [DOI] [PMID: 15987956]
[EC 2.4.1.259 created 1976 as EC 2.4.1.130, part transferred 2011 to EC 2.4.1.259, modified 2012]
 
 
EC 2.4.1.261     Relevance: 75.2%
Accepted name: dolichyl-P-Man:Man8GlcNAc2-PP-dolichol α-1,2-mannosyltransferase
Reaction: dolichyl β-D-mannosyl phosphate + α-D-Man-(1→2)-α-D-Man-(1→2)-α-D-Man-(1→3)-[α-D-Man-(1→2)-α-D-Man-(1→3)-[α-D-Man-(1→6)]-α-D-Man-(1→6)]-β-D-Man-(1→4)-β-D-GlcNAc-(1→4)-α-D-GlcNAc-diphosphodolichol = α-D-Man-(1→2)-α-D-Man-(1→2)-α-D-Man-(1→3)-[α-D-Man-(1→2)-α-D-Man-(1→3)-[α-D-Man-(1→2)-α-D-Man-(1→6)]-α-D-Man-(1→6)]-β-D-Man-(1→4)-β-D-GlcNAc-(1→4)-α-D-GlcNAc-diphosphodolichol + dolichyl phosphate
For diagram of dolichyltetradecasaccharide biosynthesis, click here
Other name(s): ALG9; ALG9 α1,2 mannosyltransferase; dolichylphosphomannose-dependent ALG9 mannosyltransferase; ALG9 mannosyltransferase; Dol-P-Man:Man8GlcNAc2-PP-Dol α-1,2-mannosyltransferase; dolichyl β-D-mannosyl phosphate:D-Man-α-(1→2)-D-Man-α-(1→2)-D-Man-α-(1→3)-[D-Man-α-(1→2)-D-Man-α-(1→3)-[D-Man-α-(1→6)]-D-Man-α-(1→6)]-D-Man-β-(1→4)-D-GlcNAc-β-(1→4)-D-GlcNAc-diphosphodolichol 2-α-D-mannosyltransferase
Systematic name: dolichyl β-D-mannosyl-phosphate:α-D-Man-(1→2)-α-D-Man-(1→2)-α-D-Man-(1→3)-[α-D-Man-(1→2)-α-D-Man-(1→3)-[α-D-Man-(1→6)]-α-D-Man-(1→6)]-β-D-Man-(1→4)-β-D-GlcNAc-(1→4)-α-D-GlcNAc-diphosphodolichol 2-α-D-mannosyltransferase (configuration-inverting)
Comments: The formation of N-glycosidic linkages of glycoproteins involves the ordered assembly of the common Glc3Man9GlcNAc2 core-oligosaccharide on the lipid carrier dolichyl diphosphate. Early mannosylation steps occur on the cytoplasmic side of the endoplasmic reticulum with GDP-Man as donor, the final reactions from Man5GlcNAc2-PP-Dol to Man9Glc-NAc2-PP-Dol on the lumenal side use dolichyl β-D-mannosyl phosphate. ALG9 mannosyltransferase catalyses the addition of two different α-1,2-mannose residues: the addition of α-1,2-mannose to Man6GlcNAc2-PP-Dol (EC 2.4.1.259) and the addition of α-1,2-mannose to Man8GlcNAc2-PP-Dol (EC 2.4.1.261).
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc
References:
1.  Vleugels, W., Keldermans, L., Jaeken, J., Butters, T.D., Michalski, J.C., Matthijs, G. and Foulquier, F. Quality control of glycoproteins bearing truncated glycans in an ALG9-defective (CDG-IL) patient. Glycobiology 19 (2009) 910–917. [DOI] [PMID: 19451548]
2.  Frank, C.G. and Aebi, M. ALG9 mannosyltransferase is involved in two different steps of lipid-linked oligosaccharide biosynthesis. Glycobiology 15 (2005) 1156–1163. [DOI] [PMID: 15987956]
[EC 2.4.1.261 created 1976 as EC 2.4.1.130, part transferred 2011 to EC 2.4.1.261, modified 2012]
 
 
EC 2.4.1.131     Relevance: 73.9%
Accepted name: GDP-Man:Man3GlcNAc2-PP-dolichol α-1,2-mannosyltransferase
Reaction: 2 GDP-α-D-mannose + α-D-Man-(1→3)-[α-D-Man-(1→6)]-β-D-Man-(1→4)-β-D-GlcNAc-(1→4)-α-D-GlcNAc-diphosphodolichol = 2 GDP + α-D-Man-(1→2)-α-D-Man-(1→2)-α-D-Man-(1→3)-[α-D-Man-(1→6)]-β-D-Man-(1→4)-β-D-GlcNAc-(1→4)-α-D-GlcNAc-diphosphodolichol
For diagram of dolichyltetradecasaccharide biosynthesis, click here
Other name(s): ALG11; ALG11 mannosyltransferase; LEW3 (gene name); At2G40190 (gene name); gmd3 (gene name); galactomannan deficiency protein 3; GDP-mannose:glycolipid 1,2-α-D-mannosyltransferase; glycolipid 2-α-mannosyltransferase; GDP-mannose:glycolipid 2-α-D-mannosyltransferase; GDP-Man:Man3GlcNAc2-PP-Dol α-1,2-mannosyltransferase; GDP-α-D-mannose:D-Man-α-(1→3)-[D-Man-α-(1→6)]-D-Man-β-(1→4)-D-GlcNAc-β-(1→4)-D-GlcNAc-diphosphodolichol 2-α-D-mannosyltransferase
Systematic name: GDP-α-D-mannose:α-D-Man-(1→3)-[α-D-Man-(1→6)]-β-D-Man-(1→4)-β-D-GlcNAc-(1→4)-α-D-GlcNAc-diphosphodolichol 2-α-D-mannosyltransferase (configuration-retaining)
Comments: The biosynthesis of asparagine-linked glycoproteins (N-linked protein glycosylation) utilizes a dolichyl diphosphate-linked glycosyl donor, which is assembled by the series of membrane-bound glycosyltransferases that comprise the dolichol pathway. ALG11 mannosyltransferase from Saccharomyces cerevisiae carries out two sequential steps in the formation of the lipid-linked core oligosaccharide, adding two mannose residues in α(1→2) linkages to the nascent oligosaccharide.
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc, CAS registry number: 74506-43-7
References:
1.  O'Reilly, M.K., Zhang, G. and Imperiali, B. In vitro evidence for the dual function of Alg2 and Alg11: essential mannosyltransferases in N-linked glycoprotein biosynthesis. Biochemistry 45 (2006) 9593–9603. [DOI] [PMID: 16878994]
2.  Absmanner, B., Schmeiser, V., Kampf, M. and Lehle, L. Biochemical characterization, membrane association and identification of amino acids essential for the function of Alg11 from Saccharomyces cerevisiae, an α1,2-mannosyltransferase catalysing two sequential glycosylation steps in the formation of the lipid-linked core oligosaccharide. Biochem. J. 426 (2010) 205–217. [DOI] [PMID: 19929855]
3.  Schutzbach, J.S., Springfield, J.D. and Jensen, J.W. The biosynthesis of oligosaccharide-lipids. Formation of an α-1,2-mannosyl-mannose linkage. J. Biol. Chem. 255 (1980) 4170–4175. [PMID: 6154707]
[EC 2.4.1.131 created 1984, modified 2011, modified 2012]
 
 
EC 3.2.1.165     Relevance: 73.4%
Accepted name: exo-1,4-β-D-glucosaminidase
Reaction: Hydrolysis of chitosan or chitosan oligosaccharides to remove successive D-glucosamine residues from the non-reducing termini
Glossary: GlcN = D-glucosamine = 2-amino-2-deoxy-D-glucopyranose
GlcNAc = N-acetyl-D-glucosamine
Other name(s): CsxA; GlcNase; exochitosanase; GlmA; exo-β-D-glucosaminidase; chitosan exo-1,4-β-D-glucosaminidase
Systematic name: chitosan exo-(1→4)-β-D-glucosaminidase
Comments: Chitosan is a partially or totally N-deacetylated chitin derivative that is found in the cell walls of some phytopathogenic fungi and comprises D-glucosamine residues with a variable content of GlcNAc residues [4]. Acts specifically on chitooligosaccharides and chitosan, having maximal activity on chitotetraose, chitopentaose and their corresponding alcohols [1]. The enzyme can degrade GlcN-GlcNAc but not GlcNAc-GlcNAc [3]. A member of the glycoside hydrolase family 2 (GH-2) [4].
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc
References:
1.  Nanjo, F., Katsumi, R. and Sakai, K. Purification and characterization of an exo-β-D-glucosaminidase, a novel type of enzyme, from Nocardia orientalis. J. Biol. Chem. 265 (1990) 10088–10094. [PMID: 2351651]
2.  Nogawa, M., Takahashi, H., Kashiwagi, A., Ohshima, K., Okada, H. and Morikawa, Y. Purification and characterization of exo-β-D-glucosaminidase from a cellulolytic fungus, Trichoderma reesei PC-3-7. Appl. Environ. Microbiol. 64 (1998) 890–895. [PMID: 16349528]
3.  Fukamizo, T., Fleury, A., Côté, N., Mitsutomi, M. and Brzezinski, R. Exo-β-D-glucosaminidase from Amycolatopsis orientalis: catalytic residues, sugar recognition specificity, kinetics, and synergism. Glycobiology 16 (2006) 1064–1072. [DOI] [PMID: 16877749]
4.  Côté, N., Fleury, A., Dumont-Blanchette, E., Fukamizo, T., Mitsutomi, M. and Brzezinski, R. Two exo-β-D-glucosaminidases/exochitosanases from actinomycetes define a new subfamily within family 2 of glycoside hydrolases. Biochem. J. 394 (2006) 675–686. [DOI] [PMID: 16316314]
5.  Ike, M., Isami, K., Tanabe, Y., Nogawa, M., Ogasawara, W., Okada, H. and Morikawa, Y. Cloning and heterologous expression of the exo-β-D-glucosaminidase-encoding gene (gls93) from a filamentous fungus, Trichoderma reesei PC-3-7. Appl. Microbiol. Biotechnol. 72 (2006) 687–695. [DOI] [PMID: 16636831]
[EC 3.2.1.165 created 2008]
 
 
EC 2.4.1.222     Relevance: 72.8%
Accepted name: O-fucosylpeptide 3-β-N-acetylglucosaminyltransferase
Reaction: transfers a β-D-GlcNAc residue from UDP-D-GlcNAc to the fucose residue of a fucosylated protein acceptor
Other name(s): O-fucosylpeptide β-1,3-N-acetylglucosaminyltransferase; fringe (ambiguous)
Systematic name: UDP-D-GlcNAc:O-L-fucosylpeptide 3-β-N-acetyl-D-glucosaminyltransferase
Comments: O-Fucosylpeptide 3-β-N-acetylglucosaminyltransferases are the products of fringe genes. O-linked fucose is an unusual form of glycosylation where the fucose is attached directly to proteins through the hydroxy groups of Ser or Thr residues.
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc, PDB, CAS registry number: 299203-70-6
References:
1.  Moloney, D.J., Panin, V.M., Johnston, S.H., Chen, J., Shao, L., Wilson, R., Wang, Y., Stanley, P., Irvine, K.D., Haltiwanger, R.S. and Vogt, T.F. Fringe is a glycosyltransferase that modifies Notch. Nature 406 (2000) 369–375. [DOI] [PMID: 10935626]
[EC 2.4.1.222 created 2002]
 
 
EC 3.2.1.114     Relevance: 72.2%
Accepted name: mannosyl-oligosaccharide 1,3-1,6-α-mannosidase
Reaction: Man5GlcNAc3-[protein] + 2 H2O = Man3GlcNAc3-[protein] + 2 α-D-mannopyranose
For diagram of mannosyl-glycoprotein n-acetylglucosaminyltransferases, click here
Glossary: Man5GlcNAc3-[protein] = [β-D-GlcNAc-(1→2)-α-D-Man-(1→3)-{α-D-Man-(1→3)-[α-D-Man-(1→6)]-α-D-Man-(1→6)}-β-D-Man-(1→4)-β-D-GlcNAc-(1→4)-β-D-GlcNAc]-N-Asn-[protein]
Man3GlcNAc3-[protein] = {β-D-GlcNAc-(1→2)-α-D-Man-(1→3)-[α-D-Man-(1→6)]-β-D-Man-(1→4)-β-D-GlcNAc-(1→4)-β-D-GlcNAc}-N-Asn-[protein]
Other name(s): MAN2A1 (gene name); MAN2A2 (gene name); mannosidase II; exo-1,3-1,6-α-mannosidase; α-D-mannosidase II; α-mannosidase II; α1-3,6-mannosidase; GlcNAc transferase I-dependent α1,3[α1,6]mannosidase; Golgi α-mannosidase II; ManII; 1,3(1,6)-α-D-mannosidase; 1,3-(1,6-)mannosyl-oligosaccharide α-D-mannohydrolase; (1→3)-(1→6)-mannosyl-oligosaccharide α-D-mannohydrolase
Systematic name: (1→3)-(1→6)-mannosyl-oligosaccharide α-D-mannohydrolase (configuration-retaining)
Comments: The enzyme, found in plants and animals, participates in the processing of N-glycans in the Golgi apparatus. It removes two mannosyl residues, one linked by α1,3 linkage, and the other linked by α1,6 linkage, both of which are removed by the same catalytic site. The enzyme is sensitive to swainsonine.
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc, PDB, CAS registry number: 82047-77-6
References:
1.  Tulsiani, D.R.P., Opheim, D.J. and Touster, O. Purification and characterization of α-D-mannosidase from rat liver golgi membranes. J. Biol. Chem. 252 (1977) 3227–3233. [PMID: 863880]
2.  Tabas, I. and Kornfeld, S. The synthesis of complex-type oligosaccharides. III. Identification of an α-D-mannosidase activity involved in a late stage of processing of complex-type oligosaccharides. J. Biol. Chem. 253 (1978) 7779–7786. [PMID: 212436]
3.  Harpaz, N. and Schachter, H. Control of glycoprotein synthesis. Processing of asparagine-linked oligosaccharides by one or more rat liver Golgi α-D-mannosidases dependent on the prior action of UDP-N-acetylglucosamine: α-D-mannoside β2-N-acetylglucosaminyltransferase I. J. Biol. Chem. 255 (1980) 4894–4902. [PMID: 6445359]
4.  Tulsiani, D.R.P., Hubbard, S.C., Robbins, P.W. and Touster, O. α-D-Mannosidases of rat liver Golgi membranes. Mannosidase II is the GlcNAcMAN5-cleaving enzyme in glycoprotein biosynthesis and mannosidases IA and IB are the enzymes converting Man9 precursors to Man5 intermediates. J. Biol. Chem. 257 (1982) 3660–3668. [PMID: 7061502]
5.  Moremen, K.W. and Robbins, P.W. Isolation, characterization, and expression of cDNAs encoding murine α-mannosidase II, a Golgi enzyme that controls conversion of high mannose to complex N-glycans. J. Cell Biol. 115 (1991) 1521–1534. [PMID: 1757461]
6.  Misago, M., Liao, Y.F., Kudo, S., Eto, S., Mattei, M.G., Moremen, K.W. and Fukuda, M.N. Molecular cloning and expression of cDNAs encoding human α-mannosidase II and a previously unrecognized α-mannosidase IIx isozyme. Proc. Natl. Acad. Sci. USA 92 (1995) 11766–11770. [DOI] [PMID: 8524845]
7.  van den Elsen, J.M., Kuntz, D.A. and Rose, D.R. Structure of Golgi α-mannosidase II: a target for inhibition of growth and metastasis of cancer cells. EMBO J. 20 (2001) 3008–3017. [DOI] [PMID: 11406577]
8.  Athanasopoulos, V.I., Niranjan, K. and Rastall, R.A. The production, purification and characterisation of two novel α-D-mannosidases from Aspergillus phoenicis. Carbohydr. Res. 340 (2005) 609–617. [DOI] [PMID: 15721331]
9.  Shah, N., Kuntz, D.A. and Rose, D.R. Golgi α-mannosidase II cleaves two sugars sequentially in the same catalytic site. Proc. Natl. Acad. Sci. USA 105 (2008) 9570–9575. [DOI] [PMID: 18599462]
10.  Rose, D.R. Structure, mechanism and inhibition of Golgi α-mannosidase II. Curr. Opin. Struct. Biol. 22 (2012) 558–562. [DOI] [PMID: 22819743]
[EC 3.2.1.114 created 1986, modified 2018]
 
 
EC 2.4.1.255     Relevance: 71.4%
Accepted name: protein O-GlcNAc transferase
Reaction: (1) UDP-N-acetyl-α-D-glucosamine + [protein]-L-serine = UDP + [protein]-3-O-(N-acetyl-β-D-glucosaminyl)-L-serine
(2) UDP-N-acetyl-α-D-glucosamine + [protein]-L-threonine = UDP + [protein]-3-O-(N-acetyl-β-D-glucosaminyl)-L-threonine
Other name(s): O-GlcNAc transferase; OGTase; O-linked N-acetylglucosaminyltransferase; uridine diphospho-N-acetylglucosamine:polypeptide β-N-acetylglucosaminyltransferase; protein O-linked β-N-acetylglucosamine transferase
Systematic name: UDP-N-α-acetyl-D-glucosamine:[protein]-3-O-N-acetyl-β-D-glucosaminyl transferase
Comments: Within higher eukaryotes post-translational modification of protein serines/threonines with N-acetylglucosamine (O-GlcNAc) is dynamic, inducible and abundant, regulating many cellular processes by interfering with protein phosphorylation. EC 2.4.1.255 (protein O-GlcNAc transferase) transfers GlcNAc onto substrate proteins and EC 3.2.1.169 (protein O-GlcNAcase) cleaves GlcNAc from the modified proteins.
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc
References:
1.  Banerjee, S., Robbins, P.W. and Samuelson, J. Molecular characterization of nucleocytosolic O-GlcNAc transferases of Giardia lamblia and Cryptosporidium parvum. Glycobiology 19 (2009) 331–336. [DOI] [PMID: 18948359]
2.  Clarke, A.J., Hurtado-Guerrero, R., Pathak, S., Schuttelkopf, A.W., Borodkin, V., Shepherd, S.M., Ibrahim, A.F. and van Aalten, D.M. Structural insights into mechanism and specificity of O-GlcNAc transferase. EMBO J. 27 (2008) 2780–2788. [DOI] [PMID: 18818698]
3.  Rao, F.V., Dorfmueller, H.C., Villa, F., Allwood, M., Eggleston, I.M. and van Aalten, D.M. Structural insights into the mechanism and inhibition of eukaryotic O-GlcNAc hydrolysis. EMBO J. 25 (2006) 1569–1578. [DOI] [PMID: 16541109]
4.  Haltiwanger, R.S., Blomberg, M.A. and Hart, G.W. Glycosylation of nuclear and cytoplasmic proteins. Purification and characterization of a uridine diphospho-N-acetylglucosamine:polypeptide β-N-acetylglucosaminyltransferase. J. Biol. Chem. 267 (1992) 9005–9013. [PMID: 1533623]
5.  Lubas, W.A., Frank, D.W., Krause, M. and Hanover, J.A. O-Linked GlcNAc transferase is a conserved nucleocytoplasmic protein containing tetratricopeptide repeats. J. Biol. Chem. 272 (1997) 9316–9324. [DOI] [PMID: 9083068]
6.  Lazarus, M.B., Nam, Y., Jiang, J., Sliz, P. and Walker, S. Structure of human O-GlcNAc transferase and its complex with a peptide substrate. Nature 469 (2011) 564–567. [DOI] [PMID: 21240259]
[EC 2.4.1.255 created 2011]
 
 
EC 2.4.1.101     Relevance: 71%
Accepted name: α-1,3-mannosyl-glycoprotein 2-β-N-acetylglucosaminyltransferase
Reaction: UDP-N-acetyl-α-D-glucosamine + Man5GlcNAc2-[protein] = UDP + Man5GlcNAc3-[protein]
For diagram of mannosyl-glycoprotein N-acetylglucosaminyltransferases, click here
Glossary: Man5GlcNAc2-[protein] = α-D-Man-(1→3)-[α-D-Man-(1→3)-[α-D-Man-(1→6)]-α-D-Man-(1→6)]-β-D-Man-(1→4)-β-D-GlcNAc-(1→4)-α-D-GlcNAc-N-Asn-[protein]
Man5GlcNAc3-[protein]= β-D-GlcNAc-(1→2)-α-D-Man-(1→3)-[α-D-Man-(1→3)-[α-D-Man-(1→6)]-α-D-Man-(1→6)]-β-D-Man-(1→4)-β-D-GlcNAc-(1→4)-α-D-GlcNAc-N-Asn-[protein]
Other name(s): MGAT1 (gene name); N-acetylglucosaminyltransferase I; N-glycosyl-oligosaccharide-glycoprotein N-acetylglucosaminyltransferase I; uridine diphosphoacetylglucosamine-α-1,3-mannosylglycoprotein β-1,2-N-acetylglucosaminyltransferase; UDP-N-acetylglucosaminyl:α-1,3-D-mannoside-β-1,2-N-acetylglucosaminyltransferase I; UDP-N-acetylglucosaminyl:α-3-D-mannoside β-1,2-N-acetylglucosaminyltransferase I; α-1,3-mannosyl-glycoprotein β-1,2-N-acetylglucosaminyltransferase; GnTI; GlcNAc-T I; UDP-N-acetyl-D-glucosamine:3-(α-D-mannosyl)-β-D-mannosyl-glycoprotein 2-β-N-acetyl-D-glucosaminyltransferase
Systematic name: UDP-N-acetyl-α-D-glucosamine:α-D-mannosyl-(1→3)-β-D-mannosyl-glycoprotein 2-β-N-acetyl-D-glucosaminyltransferase (configuration-inverting)
Comments: The enzyme, found in plants and animals, participates in the processing of N-glycans in the Golgi apparatus. Its action is required before the other N-acetylglucosaminyltransferases involved in the process (GlcNAcT-II through VI) can act. While the natural substrate (produced by EC 3.2.1.113, mannosyl-oligosaccharide 1,2-α-mannosidase) is described here, the minimal substrate recognized by the enzyme is α-D-Man-(1→3)-β-D-Man-R.
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc, PDB, CAS registry number: 102576-81-8
References:
1.  Harpaz, N. and Schachter, H. Control of glycoprotein synthesis. Bovine colostrum UDP-N-acetylglucosamine:α-D-mannoside β2-N-acetylglucosaminyltransferase I. Separation from UDP-N-acetylglucosamine:α-D-mannoside β2-N-acetylglucosaminyltransferase II, partial purification, and substrate specificity. J. Biol. Chem. 255 (1980) 4885–4893. [PMID: 6445358]
2.  Mendicino, J., Chandrasekaran, E.V., Anumula, K.R. and Davila, M. Isolation and properties of α-D-mannose:β-1,2-N-acetylglucosaminyltransferase from trachea mucosa. Biochemistry 20 (1981) 967–976. [PMID: 6452163]
3.  Oppenheimer, C.L. and Hill, R.L. Purification and characterization of a rabbit liver α1→3 mannoside β1→2 N-acetylglucosaminyltransferase. J. Biol. Chem. 256 (1981) 799–804. [PMID: 6450208]
4.  Oppenheimer, C.L., Eckhardt, A.E. and Hill, R.L. The nonidentity of porcine N-acetylglucosaminyltransferases I and II. J. Biol. Chem. 256 (1981) 11477–11482. [PMID: 6457827]
5.  Miyagi, T. and Tsuiki, S. Studies on UDP-N-acetylglucosamine : α-mannoside β-N-acetylglucosaminyltransferase of rat liver and hepatomas. Biochim. Biophys. Acta 661 (1981) 148–157. [DOI] [PMID: 6170335]
6.  Schachter, H., Narasimhan, S., Gleeson, P. and Vella, G. Glycosyltransferases involved in elongation of N-glycosidically linked oligosaccharides of the complex or N-acetyllactosamine type. Methods Enzymol. 98 (1983) 98–134. [PMID: 6366476]
7.  Vella, G.J., Paulsen, H. and Schachter, H. Control of glycoprotein synthesis. IX. A terminal Man alphal-3Man β1- sequence in the substrate is the minimum requirement for UDP-N-acetyl-D-glucosamine: α-D-mannoside (GlcNAc to Man α1-3) β2-N-acetylglucosaminyltransferase I. Can. J. Biochem. Cell Biol. 62 (1984) 409–417. [PMID: 6235906]
8.  Unligil, U.M., Zhou, S., Yuwaraj, S., Sarkar, M., Schachter, H. and Rini, J.M. X-ray crystal structure of rabbit N-acetylglucosaminyltransferase I: catalytic mechanism and a new protein superfamily. EMBO J. 19 (2000) 5269–5280. [DOI] [PMID: 11032794]
[EC 2.4.1.101 created 1983, modified 2001 (EC 2.4.1.51 created 1972, part incorporated 1984), modified 2018]
 
 
EC 2.4.2.61     Relevance: 70.7%
Accepted name: α-dystroglycan β1,4-xylosyltransferase
Reaction: UDP-α-D-xylose + 3-O-[Rib-ol-P-Rib-ol-P-3-β-D-GalNAc-(1→3)-β-D-GlcNAc-(1→4)-O-6-P-α-D-Man]-Ser/Thr-[protein] = UDP + 3-O-[β-D-Xyl-(1→4)-Rib-ol-P-Rib-ol-P-3-β-D-GalNAc-(1→3)-β-D-GlcNAc-(1→4)-O-6-P-α-D-Man]-Ser/Thr-[protein]
Other name(s): TMEM5 (gene name)
Systematic name: UDP-α-D-xylose:3-O-[Rib-ol-P-Rib-ol-P-3-β-D-GalNAc-(1→3)-β-D-GlcNAc-(1→4)-O-6-P-α-D-Man]-Ser/Thr-[protein] xylosyltransferase
Comments: This eukaryotic enzyme catalyses a step in the biosynthesis of the glycan moiety of the membrane protein α-dystroglycan. It is specific for the second ribitol 5-phosphate in the nascent glycan chain as acceptor.
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc
References:
1.  Vuillaumier-Barrot, S., Bouchet-Seraphin, C., Chelbi, M., Devisme, L., Quentin, S., Gazal, S., Laquerriere, A., Fallet-Bianco, C., Loget, P., Odent, S., Carles, D., Bazin, A., Aziza, J., Clemenson, A., Guimiot, F., Bonniere, M., Monnot, S., Bole-Feysot, C., Bernard, J.P., Loeuillet, L., Gonzales, M., Socha, K., Grandchamp, B., Attie-Bitach, T., Encha-Razavi, F. and Seta, N. Identification of mutations in TMEM5 and ISPD as a cause of severe cobblestone lissencephaly. Am. J. Hum. Genet. 91 (2012) 1135–1143. [PMID: 23217329]
2.  Manya, H., Yamaguchi, Y., Kanagawa, M., Kobayashi, K., Tajiri, M., Akasaka-Manya, K., Kawakami, H., Mizuno, M., Wada, Y., Toda, T. and Endo, T. The muscular dystrophy gene TMEM5 encodes a ribitol β1,4-xylosyltransferase required for the functional glycosylation of dystroglycan. J. Biol. Chem. 291 (2016) 24618–24627. [PMID: 27733679]
[EC 2.4.2.61 created 2018]
 
 
EC 3.1.1.103     Relevance: 69.1%
Accepted name: teichoic acid D-alanine hydrolase
Reaction: [(4-D-Ala)-(2-GlcNAc)-Rib-ol-P]n-[Gro-P]m-β-D-ManNAc-(1→4)-α-D-GlcNAc-P-peptidoglycan + n H2O = [(2-GlcNAc)-Rib-ol-P]n-[Gro-P]m-β-D-ManNAc-(1→4)-α-D-GlcNAc-P-peptidoglycan + n D-alanine
Glossary: Rib-ol = ribitol
Other name(s): fmtA (gene name)
Systematic name: teichoic acid D-alanylhydrolase
Comments: The enzyme, characterized from the bacterium Staphylococcus aureus, removes D-alanine groups from the teichoic acid produced by this organism, thus modulating the electrical charge of the bacterial surface. The activity greatly increases methicillin resistance in MRSA strains.
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc
References:
1.  Komatsuzawa, H., Sugai, M., Ohta, K., Fujiwara, T., Nakashima, S., Suzuki, J., Lee, C.Y. and Suginaka, H. Cloning and characterization of the fmt gene which affects the methicillin resistance level and autolysis in the presence of triton X-100 in methicillin-resistant Staphylococcus aureus. Antimicrob. Agents Chemother. 41 (1997) 2355–2361. [PMID: 9371333]
2.  Qamar, A. and Golemi-Kotra, D. Dual roles of FmtA in Staphylococcus aureus cell wall biosynthesis and autolysis. Antimicrob. Agents Chemother. 56 (2012) 3797–3805. [DOI] [PMID: 22564846]
3.  Rahman, M.M., Hunter, H.N., Prova, S., Verma, V., Qamar, A. and Golemi-Kotra, D. The Staphylococcus aureus methicillin resistance factor FmtA is a D-amino esterase that acts on teichoic acids. MBio 7 (2016) e02070. [DOI] [PMID: 26861022]
[EC 3.1.1.103 created 2018]
 
 
EC 2.4.1.304     Relevance: 68.8%
Accepted name: UDP-Gal:α-D-GlcNAc-diphosphoundecaprenol β-1,4-galactosyltransferase
Reaction: UDP-α-D-galactose + N-acetyl-α-D-glucosaminyl-diphospho-ditrans,octacis-undecaprenol = UDP + β-D-Gal-(1→4)-α-D-GlcNAc-diphospho-ditrans,octacis-undecaprenol
Other name(s): WfeD; UDP-Gal:GlcNAc-R 1,4-Gal-transferase; UDP-Gal:GlcNAc-pyrophosphate-lipid β-1,4-galactosyltransferase
Systematic name: UDP-α-D-galactose:N-acetyl-α-D-glucosaminyl-diphospho-ditrans,octacis-undecaprenol β-1,4-galactosyltransferase
Comments: The enzyme is involved in the the biosynthesis of the O-polysaccharide repeating unit of the bacterium Shigella boydii B14. The activity is stimulated by Mn2+ or to a lesser extent by Mg2+, Ca2+, Ni2+ or Pb2+.
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc
References:
1.  Xu, C., Liu, B., Hu, B., Han, Y., Feng, L., Allingham, J.S., Szarek, W.A., Wang, L. and Brockhausen, I. Biochemical characterization of UDP-Gal:GlcNAc-pyrophosphate-lipid β-1,4-Galactosyltransferase WfeD, a new enzyme from Shigella boydii type 14 that catalyzes the second step in O-antigen repeating-unit synthesis. J. Bacteriol. 193 (2011) 449–459. [DOI] [PMID: 21057010]
[EC 2.4.1.304 created 2013]
 
 
EC 3.2.1.169     Relevance: 68.6%
Accepted name: protein O-GlcNAcase
Reaction: (1) [protein]-3-O-(N-acetyl-β-D-glucosaminyl)-L-serine + H2O = [protein]-L-serine + N-acetyl-D-glucosamine
(2) [protein]-3-O-(N-acetyl-β-D-glucosaminyl)-L-theronine + H2O = [protein]-L-threonine + N-acetyl-D-glucosamine
Other name(s): OGA; glycoside hydrolase O-GlcNAcase; O-GlcNAcase; BtGH84; O-GlcNAc hydrolase
Systematic name: [protein]-3-O-(N-acetyl-β-D-glucosaminyl)-L-serine/threonine N-acetylglucosaminyl hydrolase
Comments: Within higher eukaryotes post-translational modification of protein serines/threonines with N-acetylglucosamine (O-GlcNAc) is dynamic, inducible and abundant, regulating many cellular processes by interfering with protein phosphorylation. EC 2.4.1.255 (protein O-GlcNAc transferase) transfers GlcNAc onto substrate proteins and EC 3.2.1.169 (protein O-GlcNAcase) cleaves GlcNAc from the modified proteins.
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc
References:
1.  Gao, Y., Wells, L., Comer, F.I., Parker, G.J. and Hart, G.W. Dynamic O-glycosylation of nuclear and cytosolic proteins: cloning and characterization of a neutral, cytosolic β-N-acetylglucosaminidase from human brain. J. Biol. Chem. 276 (2001) 9838–9845. [DOI] [PMID: 11148210]
2.  Wells, L., Gao, Y., Mahoney, J.A., Vosseller, K., Chen, C., Rosen, A. and Hart, G.W. Dynamic O-glycosylation of nuclear and cytosolic proteins: further characterization of the nucleocytoplasmic β-N-acetylglucosaminidase, O-GlcNAcase. J. Biol. Chem. 277 (2002) 1755–1761. [PMID: 11788610]
3.  Cetinbas, N., Macauley, M.S., Stubbs, K.A., Drapala, R. and Vocadlo, D.J. Identification of Asp174 and Asp175 as the key catalytic residues of human O-GlcNAcase by functional analysis of site-directed mutants. Biochemistry 45 (2006) 3835–3844. [DOI] [PMID: 16533067]
4.  Dennis, R.J., Taylor, E.J., Macauley, M.S., Stubbs, K.A., Turkenburg, J.P., Hart, S.J., Black, G.N., Vocadlo, D.J. and Davies, G.J. Structure and mechanism of a bacterial β-glucosaminidase having O-GlcNAcase activity. Nat. Struct. Mol. Biol. 13 (2006) 365–371. [DOI] [PMID: 16565725]
5.  Kim, E.J., Kang, D.O., Love, D.C. and Hanover, J.A. Enzymatic characterization of O-GlcNAcase isoforms using a fluorogenic GlcNAc substrate. Carbohydr. Res. 341 (2006) 971–982. [DOI] [PMID: 16584714]
6.  Dong, D.L. and Hart, G.W. Purification and characterization of an O-GlcNAc selective N-acetyl-β-D-glucosaminidase from rat spleen cytosol. J. Biol. Chem. 269 (1994) 19321–19330. [PMID: 8034696]
[EC 3.2.1.169 created 2011]
 
 
EC 3.2.1.106     Relevance: 68.2%
Accepted name: mannosyl-oligosaccharide glucosidase
Reaction: Glc3Man9GlcNAc2-[protein] + H2O = Glc2Man9GlcNAc2-[protein] + β-D-glucopyranose
Glossary: Glc3Man9GlcNAc2 = [α-D-Glc-(1→2)-α-D-Glc-(1→3)-α-D-Glc-(1→3)-α-D-Man-(1→2)-α-D-Man-(1→2)-α-D-Man-(1→3)-{α-D-Man-(1→2)-α-D-Man-(1→3)-[α-D-Man-(1→2)-α-D-Man-(1→6)]-α-D-Man-(1→6)}-β-D-Man-(1→4)-β-D-GlcNAc-(1→4)-β-D-GlcNAc]-N-Asn-[protein]
Glc2Man9GlcNAc2-[protein] = [α-D-Glc-(1→3)-α-D-Glc-(1→3)-α-D-Man-(1→2)-α-D-Man-(1→2)-α-D-Man-(1→3)-{α-D-Man-(1→2)-α-D-Man-(1→3)-[α-D-Man-(1→2)-α-D-Man-(1→6)]-α-D-Man-(1→6)}-β-D-Man-(1→4)-β-D-GlcNAc-(1→4)-β-D-GlcNAc]-N-Asn-[protein]
Other name(s): Glc3Man9NAc2 oligosaccharide glucosidase; trimming glucosidase I; CWH41 (gene name); MOGS (gene name); mannosyl-oligosaccharide glucohydrolase
Systematic name: Glc3Man9GlcNAc2-[protein] glucohydrolase (configuration-inverting)
Comments: This enzyme catalyses the first step in the processing of the N-glycan tetradecasaccharide precursor Glc3Man9GlcNAc2, which takes place in the endoplasmic reticulum, by removing the distal α-1,2-linked glucose residue. This and subsequent processing steps are required before complex N-glycans can be synthesized.
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc, CAS registry number: 78413-07-7
References:
1.  Elting, J.J., Chen, W.W. and Lennarz, J. Characterization of a glucosidase involved in an initial step in the processing of oligosaccharide chains. J. Biol. Chem. 255 (1980) 2325–2331. [PMID: 7358674]
2.  Grinna, L.S. and Robbins, P.W. Glycoprotein biosynthesis. Rat liver microsomal glucosidases which process oligosaccharides. J. Biol. Chem. 254 (1979) 8814–8818. [PMID: 479161]
3.  Kilker, R.D., Saunier, B., Tkacz, J.S. and Herscovics, A. Partial purification from Saccharomyces cerevisiae of a soluble glucosidase which removes the terminal glucose from the oligosaccharide Glc3Man9GlcNAc2. J. Biol. Chem. 256 (1981) 5299–5603. [PMID: 7014569]
4.  Grinna, L.S. and Robbins, P.W. Substrate specificities of rat liver microsomal glucosidases which process glycoproteins. J. Biol. Chem. 255 (1980) 2255–2258. [PMID: 7358666]
5.  Mark, M.J. and Kornfeld, S. Partial purification and characterization of the glucosidases involved in the processing of asparagine-linked oligosaccharides. Arch. Biochem. Biophys. 199 (1980) 249–258. [DOI] [PMID: 7356331]
[EC 3.2.1.106 created 1984, modified 2018]
 
 
EC 3.2.1.130     Relevance: 67.7%
Accepted name: glycoprotein endo-α-1,2-mannosidase
Reaction: GlcMan9GlcNAc2-[protein] + H2O = Man8GlcNAc2-[protein] (isomer 8A1,2,3B1,2) + α-D-glucosyl-(1→3)-α-D-mannopyranose
Glossary: GlcMan9GlcNAc2-[protein] = {α-D-Glc-(1→3)-α-D-Man-(1→2)-α-D-Man-(1→2)-α-D-Man-(1→3)-[α-D-Man-(1→2)-α-D-Man-(1→3)-[α-D-Man-(1→2)-α-D-Man-(1→6)]-α-D-Man-(1→6)]-β-D-Man-(1→4)-β-D-GlcNAc-(1→4)-α-D-GlcNAc}-N-Asn-[protein]
Man8GlcNAc2-[protein] (isomer 8A1,2,3B1,2) = {α-D-Man-(1→2)-α-D-Man-(1→3)-[α-D-Man-(1→2)-α-D-Man-(1→3)-[α-D-Man-(1→2)-α-D-Man-(1→6)]-α-D-Man-(1→6)]-β-D-Man-(1→4)-β-D-GlcNAc-(1→4)-α-D-GlcNAc}-N-Asn-[protein]
Other name(s): glucosylmannosidase; endo-α-D-mannosidase; endo-α-mannosidase; endomannosidase; glucosyl mannosidase; MANEA (gene name); glycoprotein glucosylmannohydrolase
Systematic name: glycoprotein glucosylmannohydrolase (configuration-retaining)
Comments: The enzyme catalyses the hydrolysis of the terminal α-D-glucosyl-(1→3)-D-mannosyl unit from the GlcMan9(GlcNAc)2 oligosaccharide component of N-glucosylated proteins during their processing in the Golgi apparatus. The name for the isomer is based on a nomenclature proposed by Prien et al [7].
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc, CAS registry number: 108022-16-8
References:
1.  Lubas, W.A. and Spiro, R.G. Golgi endo-α-D-mannosidase from rat liver, a novel N-linked carbohydrate unit processing enzyme. J. Biol. Chem. 262 (1987) 3775–3781. [PMID: 3818665]
2.  Tulsiani, D.R.P., Coleman, V.P. and Touster, O. Asparagine-linked glycoprotein biosynthesis in rat brain: identification of glucosidase I, glucosidase II, and endomannosidase (glucosyl mannosidase). Arch. Biochem. Biophys. 277 (1990) 114–121. [DOI] [PMID: 2407194]
3.  Hiraizumi, S., Spohr, U. and Spiro, R.G. Ligand affinity chromatographic purification of rat liver Golgi endomannosidase. J. Biol. Chem. 269 (1994) 4697–4700. [PMID: 8106437]
4.  Spiro, M.J., Bhoyroo, V.D. and Spiro, R.G. Molecular cloning and expression of rat liver endo-α-mannosidase, an N-linked oligosaccharide processing enzyme. J. Biol. Chem. 272 (1997) 29356–29363. [DOI] [PMID: 9361017]
5.  Hamilton, S.R., Li, H., Wischnewski, H., Prasad, A., Kerley-Hamilton, J.S., Mitchell, T., Walling, A.J., Davidson, R.C., Wildt, S. and Gerngross, T.U. Intact α-1,2-endomannosidase is a typical type II membrane protein. Glycobiology 15 (2005) 615–624. [DOI] [PMID: 15677381]
6.  Hardt, B., Volker, C., Mundt, S., Salska-Navarro, M., Hauptmann, M. and Bause, E. Human endo-α1,2-mannosidase is a Golgi-resident type II membrane protein. Biochimie 87 (2005) 169–179. [DOI] [PMID: 15760709]
7.  Prien, J.M., Ashline, D.J., Lapadula, A.J., Zhang, H. and Reinhold, V.N. The high mannose glycans from bovine ribonuclease B isomer characterization by ion trap MS. J. Am. Soc. Mass Spectrom. 20 (2009) 539–556. [DOI] [PMID: 19181540]
[EC 3.2.1.130 created 1990, modified 2017]
 
 
EC 2.4.1.305     Relevance: 67.1%
Accepted name: UDP-Glc:α-D-GlcNAc-glucosaminyl-diphosphoundecaprenol β-1,3-glucosyltransferase
Reaction: UDP-α-D-glucose + N-acetyl-α-D-glucosaminyl-diphospho-ditrans,octacis-undecaprenol = UDP + β-D-Glc-(1→3)-α-D-GlcNAc-diphospho-ditrans,octacis-undecaprenol
Other name(s): WfaP; WfgD; UDP-Glc:GlcNAc-pyrophosphate-lipid β-1,3-glucosyltransferase; UDP-Glc:GlcNAc-diphosphate-lipid β-1,3-glucosyltransferase
Systematic name: UDP-α-D-glucose:N-acetyl-α-D-glucosaminyl-diphospho-ditrans,octacis-undecaprenol β-1,3-glucosyltransferase
Comments: The enzyme is involved in the the biosynthesis of the O-polysaccharide repeating unit of the bacterium Escherichia coli serotype O56 and serotype O152.
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc
References:
1.  Brockhausen, I., Hu, B., Liu, B., Lau, K., Szarek, W.A., Wang, L. and Feng, L. Characterization of two β-1,3-glucosyltransferases from Escherichia coli serotypes O56 and O152. J. Bacteriol. 190 (2008) 4922–4932. [DOI] [PMID: 18487334]
[EC 2.4.1.305 created 2013]
 
 
EC 2.4.1.303     Relevance: 66.5%
Accepted name: UDP-Gal:α-D-GlcNAc-diphosphoundecaprenol β-1,3-galactosyltransferase
Reaction: UDP-α-D-galactose + N-acetyl-α-D-glucosaminyl-diphospho-ditrans,octacis-undecaprenol = UDP + β-D-Gal-(1→3)-α-D-GlcNAc-diphospho-ditrans,octacis-undecaprenol
Other name(s): WbbD; WbbD β3Gal-transferase; UDP-Gal:GlcNAc-R β1,3-galactosyltransferase; UDP-Gal:GlcNAcα-pyrophosphate-R β1,3-galactosyltransferase; UDP-Gal:GlcNAc-R galactosyltransferase
Systematic name: UDP-α-D-galactose:N-acetyl-α-D-glucosaminyl-diphospho-ditrans,octacis-undecaprenol 3-β-galactosyltransferase (configuration-inverting)
Comments: The enzyme is involved in the the biosynthesis of the O-antigen repeating unit of Escherichia coli O7:K1 (VW187). Requires Mn2+. cf. EC 2.4.1.343, UDP-Gal:α-D-GlcNAc-diphosphoundecaprenol α-1,3-galactosyltransferase.
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc
References:
1.  Riley, J.G., Menggad, M., Montoya-Peleaz, P.J., Szarek, W.A., Marolda, C.L., Valvano, M.A., Schutzbach, J.S. and Brockhausen, I. The wbbD gene of E. coli strain VW187 (O7:K1) encodes a UDP-Gal: GlcNAcα-pyrophosphate-R β1,3-galactosyltransferase involved in the biosynthesis of O7-specific lipopolysaccharide. Glycobiology 15 (2005) 605–613. [DOI] [PMID: 15625181]
2.  Brockhausen, I., Riley, J.G., Joynt, M., Yang, X. and Szarek, W.A. Acceptor substrate specificity of UDP-Gal: GlcNAc-R β1,3-galactosyltransferase (WbbD) from Escherichia coli O7:K1. Glycoconj. J. 25 (2008) 663–673. [DOI] [PMID: 18536883]
[EC 2.4.1.303 created 2013, modified 2017]
 
 
EC 3.2.1.210     Relevance: 60.6%
Accepted name: endoplasmic reticulum Man8GlcNAc2 1,2-α-mannosidase
Reaction: Man8GlcNAc2-[protein] (isomer 8A1,2,3B1,3) + H2O = Man7GlcNAc2-[protein] (isomer 7A1,2,3B3) + D-mannopyranose
Glossary: Man8GlcNAc2-[protein] (isomer 8A1,2,3B1,3) = {α-D-Man-(1→2)-α-D-Man-(1→2)-α-D-Man-(1→3)-[α-D-Man-(1→3)-[α-D-Man-(1→2)-α-D-Man-(1→6)]-α-D-Man-(1→6)]-β-D-Man-(1→4)-β-D-GlcNAc-(1→4)-α-D-GlcNAc}-N-Asn-[protein]
Man7GlcNAc2-[protein] (isomer 7A1,2,3B3) = {α-D-Man-(1→2)-α-D-Man-(1→2)-α-D-Man-(1→3)-[α-D-Man-(1→2)-α-D-Man-(1→3)-[α-D-Man-(1→6)]-α-D-Man-(1→6)]-β-D-Man-(1→4)-β-D-GlcNAc-(1→4)-α-D-GlcNAc}-N-Asn-[protein]
Other name(s): MNL1 (gene name)
Systematic name: Man8GlcNAc2-[protein] 2-α-mannohydrolase (configuration-inverting)
Comments: In yeast this activity is catalysed by a dedicated enzyme that processes unfolded protein-bound Man8GlcNAc2 N-glycans within the endoplasmic reticulum to Man7GlcNAc2. The exposed α-1,6-linked mannose residue in the product enables the recognition by the YOS9 lectin, targeting the proteins for degradation. In mammalian cells this activity is part of the regular processing of N-glycosylated proteins, and is not associated with protein degradation. It is carried out by EC 3.2.1.113, Golgi mannosyl-oligosaccharide 1,2-α-mannosidase. The names of the isomers listed here are based on a nomenclature system proposed by Prien et al [5].
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc
References:
1.  Nakatsukasa, K., Nishikawa, S., Hosokawa, N., Nagata, K. and Endo, T. Mnl1p, an α -mannosidase-like protein in yeast Saccharomyces cerevisiae, is required for endoplasmic reticulum-associated degradation of glycoproteins. J. Biol. Chem. 276 (2001) 8635–8638. [PMID: 11254655]
2.  Jakob, C.A., Bodmer, D., Spirig, U., Battig, P., Marcil, A., Dignard, D., Bergeron, J.J., Thomas, D.Y. and Aebi, M. Htm1p, a mannosidase-like protein, is involved in glycoprotein degradation in yeast. EMBO Rep. 2 (2001) 423–430. [PMID: 11375935]
3.  Quan, E.M., Kamiya, Y., Kamiya, D., Denic, V., Weibezahn, J., Kato, K. and Weissman, J.S. Defining the glycan destruction signal for endoplasmic reticulum-associated degradation. Mol. Cell 32 (2008) 870–877. [PMID: 19111666]
4.  Clerc, S., Hirsch, C., Oggier, D.M., Deprez, P., Jakob, C., Sommer, T. and Aebi, M. Htm1 protein generates the N-glycan signal for glycoprotein degradation in the endoplasmic reticulum. J. Cell Biol. 184 (2009) 159–172. [PMID: 19124653]
5.  Prien, J.M., Ashline, D.J., Lapadula, A.J., Zhang, H. and Reinhold, V.N. The high mannose glycans from bovine ribonuclease B isomer characterization by ion trap MS. J. Am. Soc. Mass Spectrom. 20 (2009) 539–556. [DOI] [PMID: 19181540]
6.  Chantret, I., Kodali, V.P., Lahmouich, C., Harvey, D.J. and Moore, S.E. Endoplasmic reticulum-associated degradation (ERAD) and free oligosaccharide generation in Saccharomyces cerevisiae. J. Biol. Chem. 286 (2011) 41786–41800. [PMID: 21979948]
[EC 3.2.1.210 created 2019]
 
 
EC 2.4.1.149     Relevance: 60.6%
Accepted name: N-acetyllactosaminide β-1,3-N-acetylglucosaminyltransferase
Reaction: UDP-N-acetyl-α-D-glucosamine + β-D-galactosyl-(1→4)-N-acetyl-β-D-glucosaminyl-R = UDP + N-acetyl-β-D-glucosaminyl-(1→3)-β-D-galactosyl-(1→4)-N-acetyl-β-D-glucosaminyl-R
Other name(s): uridine diphosphoacetylglucosamine-acetyllactosaminide β1→3-acetylglucosaminyltransferase; poly-N-acetyllactosamine extension enzyme; Galβ1→4GlcNAc-R β1→3 N-acetylglucosaminyltransferase; UDP-GlcNAc:GalR β-D-3-N-acetylglucosaminyltransferase; N-acetyllactosamine β(1-3)N-acetylglucosaminyltransferase; UDP-GlcNAc:Galβ1→4GlcNAcβ-Rβ1→3-N-acetylglucosaminyltransferase; GnTE; UDP-N-acetyl-D-glucosamine:β-D-galactosyl-1,4-N-acetyl-D-glucosamine β-1,3-acetyl-D-glucosaminyltransferase; β-galactosyl-N-acetylglucosaminylgalactosylglucosyl-ceramide β-1,3-acetylglucosaminyltransferase; UDP-N-acetyl-D-glucosamine:β-D-galactosyl-(1→4)-N-acetyl-D-glucosamine 3-β-N-acetyl-D-glucosaminyltransferase
Systematic name: UDP-N-acetyl-α-D-glucosamine:β-D-galactosyl-(1→4)-N-acetyl-β-D-glucosaminyl-R 3-β N-acetylglucosaminyltransferase (configuration-inverting)
Comments: Acts on β-galactosyl-1,4-N-acetylglucosaminyl termini on glycoproteins, glycolipids, and oligosaccharides.
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc, CAS registry number: 85638-39-7
References:
1.  Van den Eijnden, D.H., Winterwerp, H., Smeeman, P. and Schiphorst, W.E.C.M. Novikoff ascites tumor cells contain N-acetyllactosaminide β1→3 and β1→6 N-acetylglucosaminyltransferase activity. J. Biol. Chem. 258 (1983) 3435–3437. [PMID: 6219989]
2.  Basu, M. and Basu, S. Biosynthesis in vitro of Ii core glycosphingolipids from neolactotetraosylceramide by β 1-3- and β 1-6-N-acetylglucosaminyltransferases from mouse T-lymphoma. J. Biol. Chem. 259 (1984) 12557–12562. [PMID: 6238026]
3.  Takeya, A., Hosomi, O. and Kogure, T. The presence of N-acetyllactosamine and lactose: β (1-3)N-acetylglucosaminyltransferase activity in human urine. Jpn. J. Med. Sci. Biol. 38 (1985) 1–8. [PMID: 3160874]
[EC 2.4.1.149 created 1984 (EC 2.4.1.163 created 1989, incorporated 2016), modified 2016]
 
 
EC 2.4.1.212     Relevance: 60%
Accepted name: hyaluronan synthase
Reaction: (1) UDP-N-acetyl-α-D-glucosamine + β-D-glucuronosyl-(1→3)-N-acetyl-β-D-glucosaminyl-(1→4)-[nascent hyaluronan] = UDP + N-acetyl-β-D-glucosaminyl-(1→4)-β-D-glucuronosyl-(1→3)-N-acetyl-β-D-glucosaminyl-(1→4)-[nascent hyaluronan]
(2) UDP-α-D-glucuronate + N-acetyl-β-D-glucosaminyl-(1→4)-β-D-glucuronosyl-(1→3)-[nascent hyaluronan] = UDP + β-D-glucuronosyl-(1→3)-N-acetyl-β-D-glucosaminyl-(1→4)-β-D-glucuronosyl-(1→3)-[nascent hyaluronan]
For diagram of reaction, click here
Glossary: GlcA = glucuronic acid
Other name(s): spHAS; seHAS; Alternating UDP-α-N-acetyl-D-glucosamine:β-D-glucuronosyl-(1→3)-[nascent hyaluronan] 4-N-acetyl-β-D-glucosaminyltransferase and UDP-α-D-glucuronate:N-acetyl-β-D-glucosaminyl-(1→4)-[nascent hyaluronan] 3-β-D-glucuronosyltransferase
Systematic name: Alternating UDP-N-acetyl-α-D-glucosamine:β-D-glucuronosyl-(1→3)-[nascent hyaluronan] 4-N-acetyl-β-D-glucosaminyltransferase and UDP-α-D-glucuronate:N-acetyl-β-D-glucosaminyl-(1→4)-[nascent hyaluronan] 3-β-D-glucuronosyltransferase (configuration-inverting)
Comments: The enzyme from Streptococcus Group A and Group C requires Mg2+. The enzyme adds GlcNAc to nascent hyaluronan when the non-reducing end is GlcA, but it adds GlcA when the non-reducing end is GlcNAc [3]. The enzyme is highly specific for UDP-GlcNAc and UDP-GlcA; no copolymerization is observed if either is replaced by UDP-Glc, UDP-Gal, UDP-GalNAc or UDP-GalA. Similar enzymes have been found in a variety of organisms.
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc, CAS registry number: 39346-43-5
References:
1.  DeAngelis, P.L., Papaconstantinou, J. and Weigel, P.H. Molecular cloning, identification and sequence of the hyaluronan synthase gene from Group A Streptococcus pyogenes. J. Biol. Chem. 268 (1993) 19181–19184. [PMID: 8366070]
2.  Jing, W. and DeAngelis, P.L. Dissection of the two transferase activities of the Pasteurella multocida hyaluronan synthase: two active sites exist in one polypeptide. Glycobiology 10 (2000) 883–889. [DOI] [PMID: 10988250]
3.  DeAngelis, P.L. Molecular directionality of polysaccharide polymerization by the Pasteurella multocida hyaluronan synthase. J. Biol. Chem. 274 (1999) 26557–26562. [DOI] [PMID: 10473619]
4.  Tlapak-Simmons, V.L., Baron, C.A. and Weigel, P.H. Characterization of the purified hyaluronan synthase from Streptococcus equisimilis. Biochemistry 43 (2004) 9234–9242. [DOI] [PMID: 15248781]
[EC 2.4.1.212 created 2001, modified 2007]
 
 
EC 2.4.1.141     Relevance: 59.7%
Accepted name: N-acetylglucosaminyldiphosphodolichol N-acetylglucosaminyltransferase
Reaction: UDP-N-acetyl-α-D-glucosamine + N-acetyl-α-D-glucosaminyl-diphosphodolichol = UDP + N-acetyl-β-D-glucosaminyl-(1→4)-N-acetyl-α-D-glucosaminyl-diphosphodolichol
For diagram of dolichyltetradecasaccharide biosynthesis, click here
Glossary: N-acetyl-β-D-glucosaminyl-(1→4)-N-acetyl-α-D-glucosaminyl-diphosphodolichol = N,N′-diacetylchitobiosyl-diphosphodolichol
Other name(s): UDP-GlcNAc:dolichyl-pyrophosphoryl-GlcNAc GlcNAc transferase; uridine diphosphoacetylglucosamine-dolichylacetylglucosamine pyrophosphate acetylglucosaminyltransferase; N,N′-diacetylchitobiosylpyrophosphoryldolichol synthase; UDP-N-acetyl-D-glucosamine:N-acetyl-D-glucosaminyl-diphosphodolichol N-acetyl-D-glucosaminyltransferase
Systematic name: UDP-N-acetyl-α-D-glucosamine:N-acetyl-α-D-glucosaminyl-diphosphodolichol 4-β-N-acetyl-D-glucosaminyltransferase (configuration-inverting)
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc, CAS registry number: 75536-54-8
References:
1.  Sharma, C.B., Lehle, L. and Tanner, W. Solubilization and characterization of the initial enzymes of the dolichol pathway from yeast. Eur. J. Biochem. 126 (1982) 319–325. [DOI] [PMID: 6215245]
2.  Turco, S.J. and Heath, E.C. Glucuronosyl-N-acetylglucosaminyl pyrophosphoryldolichol. Formation in SV40-transformed human lung fibroblasts and biosynthesis in rat lung microsomal preparations. J. Biol. Chem. 252 (1977) 2918–2928. [PMID: 192724]
[EC 2.4.1.141 created 1984]
 
 
EC 6.3.5.13     Relevance: 59.4%
Accepted name: lipid II isoglutaminyl synthase (glutamine-hydrolysing)
Reaction: ATP + β-D-GlcNAc-(1→4)-Mur2Ac(oyl-L-Ala-γ-D-Glu-L-Lys-D-Ala-D-Ala)-diphospho-ditrans,octacis-undecaprenol + L-glutamine + H2O = ADP + phosphate + β-D-GlcNAc-(1→4)-MurNAc-L-Ala-D-isoglutaminyl-L-Lys-D-Ala-D-Ala-diphospho-ditrans,octacis-undecaprenol + L-glutamate (overall reaction)
(1a) L-glutamine + H2O = L-glutamate + NH3
(1b) ATP + β-D-GlcNAc-(1→4)-Mur2Ac(oyl-L-Ala-γ-D-Glu-L-Lys-D-Ala-D-Ala)-diphospho-ditrans,octacis-undecaprenol = ADP + β-D-GlcNAc-(1→4)-MurNAc-L-Ala-γ-D-O-P-Glu-L-Lys-D-Ala-D-Ala-diphospho-ditrans,octacis-undecaprenol
(1c) β-D-GlcNAc-(1→4)-Mur2Ac(oyl-L-Ala-γ-D-O-P-Glu-L-Lys-D-Ala-D-Ala)-diphospho-ditrans,octacis-undecaprenol + NH3 = β-D-GlcNAc-(1→4)-MurNAc-L-Ala-D-isoglutaminyl-L-Lys-D-Ala-D-Ala-diphospho-ditrans,octacis-undecaprenol + phosphate
Glossary: lipid II = undecaprenyldiphospho-N-acetyl-(N-acetylglucosaminyl)muramoyl peptide; the peptide element refers to L-alanyl-D-γ-glutamyl-L-lysyl/meso-2,6-diaminopimelyl-D-alanyl-D-alanine or a modified version thereof = undecaprenyldiphospho-4-O-(N-acetyl-β-D-glucosaminyl)-3-O-peptidyl-α-N-acetylmuramate; the peptide element refers to L-alanyl-D-γ-glutamyl-L-lysyl/meso-2,6-diaminopimelyl-D-alanyl-D-alanine or a modified version thereof
Other name(s): MurT/GatD; MurT/GatD complex
Systematic name: β-D-GlcNAc-(1→4)-Mur2Ac(oyl-L-Ala-γ-D-Glu-L-Lys-D-Ala-D-Ala)-diphospho-ditrans,octacis-undecaprenol:L-glutamine amidoligase (ADP-forming)
Comments: The enzyme complex, found in Gram-positive bacteria, consists of two subunits. A glutaminase subunit (cf. EC 3.5.1.2, glutaminase) produces an ammonia molecule that is channeled to a ligase subunit, which adds it to the activated D-glutamate residue of lipid II, converting it to an isoglutamine residue.
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc
References:
1.  Munch, D., Roemer, T., Lee, S.H., Engeser, M., Sahl, H.G. and Schneider, T. Identification and in vitro analysis of the GatD/MurT enzyme-complex catalyzing lipid II amidation in Staphylococcus aureus. PLoS Pathog. 8:e1002509 (2012). [PMID: 22291598]
2.  Noldeke, E.R., Muckenfuss, L.M., Niemann, V., Muller, A., Stork, E., Zocher, G., Schneider, T. and Stehle, T. Structural basis of cell wall peptidoglycan amidation by the GatD/MurT complex of Staphylococcus aureus. Sci. Rep. 8:12953 (2018). [PMID: 30154570]
3.  Morlot, C., Straume, D., Peters, K., Hegnar, O.A., Simon, N., Villard, A.M., Contreras-Martel, C., Leisico, F., Breukink, E., Gravier-Pelletier, C., Le Corre, L., Vollmer, W., Pietrancosta, N., Havarstein, L.S. and Zapun, A. Structure of the essential peptidoglycan amidotransferase MurT/GatD complex from Streptococcus pneumoniae. Nat. Commun. 9:3180 (2018). [PMID: 30093673]
[EC 6.3.5.13 created 2019]
 
 
EC 3.2.1.113     Relevance: 58.6%
Accepted name: mannosyl-oligosaccharide 1,2-α-mannosidase
Reaction: (1) Man9GlcNAc2-[protein] + 4 H2O = Man5GlcNAc2-[protein] + 4 β-D-mannopyranose (overall reaction)
(1a) Man9GlcNAc2-[protein] + H2O = Man8GlcNAc2-[protein] (isomer 8A1,2,3B1,2) + β-D-mannopyranose
(1b) Man8GlcNAc2-[protein] (isomer 8A1,2,3B1,2) + H2O = Man7GlcNAc2-[protein] (isomer 7A1,2,3B2) + β-D-mannopyranose
(1c) Man7GlcNAc2-[protein] (isomer 7A1,2,3B2) + H2O = Man6GlcNAc2-[protein] (isomer 6A1,2B2) + β-D-mannopyranose
(1d) Man6GlcNAc2-[protein] (isomer 6A1,2B2) + H2O = Man5GlcNAc2-[protein] + β-D-mannopyranose
(2) Man8GlcNAc2-[protein] (isomer 8A1,2,3B1,3) + 3 H2O = Man5GlcNAc2-[protein] + 3 β-D-mannopyranose (overall reaction)
(2a) Man8GlcNAc2-[protein] (isomer 8A1,2,3B1,3) + H2O = Man7GlcNAc2-[protein] (isomer 7A1,2,3B1) + β-D-mannopyranose
(2b) Man7GlcNAc2-[protein] (isomer 7A1,2,3B1) + H2O = Man6GlcNAc2-[protein] (isomer 6A1,2,3) + β-D-mannopyranose
(2c) Man6GlcNAc2-[protein] (isomer 6A1,2,3) + H2O = Man5GlcNAc2-[protein] + β-D-mannopyranose
Glossary: Man9GlcNAc2-[protein] = [α-D-Man-(1→2)-α-D-Man-(1→2)-α-D-Man-(1→3)-{α-D-Man-(1→2)-α-D-Man-(1→3)-[α-D-Man-(1→2)-α-D-Man-(1→6)]-α-D-Man-(1→6)}-β-D-Man-(1→4)-β-D-GlcNAc-(1→4)-β-D-GlcNAc]-N-Asn-[protein]
Man8GlcNAc2-[protein] (isomer 8A1,2,3B1,3) = [α-D-Man-(1→2)-α-D-Man-(1→2)-α-D-Man-(1→3)-{α-D-Man-(1→3)-[α-D-Man-(1→2)-α-D-Man-(1→6)]-α-D-Man-(1→6)}-β-D-Man-(1→4)-β-D-GlcNAc-(1→4)-β-D-GlcNAc]-N-Asn-[protein]
Man5GlcNAc2-[protein] = [α-D-Man-(1→3)-{α-D-Man-(1→3)-[α-D-Man-(1→6)]-α-D-Man-(1→6)}-β-D-Man-(1→4)-β-D-GlcNAc-(1→4)-β-D-GlcNAc]-N-Asn-[protein]
Other name(s): mannosidase 1A; mannosidase 1B; 1,2-α-mannosidase; exo-α-1,2-mannanase; mannose-9 processing α-mannosidase; glycoprotein processing mannosidase I; mannosidase I; Man9-mannosidase; ManI; 1,2-α-mannosyl-oligosaccharide α-D-mannohydrolase; MAN1A1 (gene name); MAN1A2 (gene name); MAN1C1 (gene name); 2-α-mannosyl-oligosaccharide α-D-mannohydrolase
Systematic name: Man9GlcNAc2-[protein] α-2-mannohydrolase (configuration-inverting)
Comments: This family of mammalian enzymes, located in the Golgi system, participates in the maturation process of N-glycans that leads to formation of hybrid and complex structures. The enzymes catalyse the hydrolysis of the four (1→2)-linked α-D-mannose residues from the Man9GlcNAc2 oligosaccharide attached to target proteins as described in reaction (1). Alternatively, the enzymes act on the Man8GlcNAc2 isomer formed by EC 3.2.1.209, endoplasmic reticulum Man9GlcNAc2 1,2-α-mannosidase, as described in reaction (2). The enzymes are type II membrane proteins, require Ca2+, and use an inverting mechanism. While all three human enzymes can catalyse the reactions listed here, some of the enzymes can additionally catalyse hydrolysis in an alternative order, generating additional isomeric intermediates, although the final product is the same. The names of the isomers listed here are based on a nomenclature system proposed by Prien et al [7].
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc, PDB, CAS registry number: 9068-25-1
References:
1.  Tabas, I. and Kornfeld, S. Purification and characterization of a rat liver Golgi α-mannosidase capable of processing asparagine-linked oligosaccharides. J. Biol. Chem. 254 (1979) 11655–11663. [PMID: 500665]
2.  Tulsiani, D.R.P., Hubbard, S.C., Robbins, P.W. and Touster, O. α-D-Mannosidases of rat liver Golgi membranes. Mannosidase II is the GlcNAcMAN5-cleaving enzyme in glycoprotein biosynthesis and mannosidases IA and IB are the enzymes converting Man9 precursors to Man5 intermediates. J. Biol. Chem. 257 (1982) 3660–3668. [PMID: 7061502]
3.  Bieberich, E. and Bause, E. Man9-mannosidase from human kidney is expressed in COS cells as a Golgi-resident type II transmembrane N-glycoprotein. Eur. J. Biochem. 233 (1995) 644–649. [PMID: 7588811]
4.  Tremblay, L.O., Campbell Dyke, N. and Herscovics, A. Molecular cloning, chromosomal mapping and tissue-specific expression of a novel human α1,2-mannosidase gene involved in N-glycan maturation. Glycobiology 8 (1998) 585–595. [PMID: 9592125]
5.  Lal, A., Pang, P., Kalelkar, S., Romero, P.A., Herscovics, A. and Moremen, K.W. Substrate specificities of recombinant murine Golgi α1,2-mannosidases IA and IB and comparison with endoplasmic reticulum and Golgi processing α1,2-mannosidases. Glycobiology 8 (1998) 981–995. [PMID: 9719679]
6.  Tremblay, L.O. and Herscovics, A. Characterization of a cDNA encoding a novel human Golgi α 1, 2-mannosidase (IC) involved in N-glycan biosynthesis. J. Biol. Chem. 275 (2000) 31655–31660. [PMID: 10915796]
7.  Prien, J.M., Ashline, D.J., Lapadula, A.J., Zhang, H. and Reinhold, V.N. The high mannose glycans from bovine ribonuclease B isomer characterization by ion trap MS. J. Am. Soc. Mass Spectrom. 20 (2009) 539–556. [DOI] [PMID: 19181540]
[EC 3.2.1.113 created 1986, modified 2019]
 
 
EC 6.3.1.12     Relevance: 58.3%
Accepted name: D-aspartate ligase
Reaction: ATP + D-aspartate + [β-GlcNAc-(1→4)-Mur2Ac(oyl-L-Ala-γ-D-Glu-L-Lys-D-Ala-D-Ala)]n = [β-GlcNAc-(1→4)-Mur2Ac(oyl-L-Ala-γ-D-Glu-6-N-(β-D-Asp)-L-Lys-D-Ala-D-Ala)]n + ADP + phosphate
For diagram of reaction, click here
Other name(s): Aslfm; UDP-MurNAc-pentapeptide:D-aspartate ligase; D-aspartic acid-activating enzyme
Systematic name: D-aspartate:[β-GlcNAc-(1→4)-Mur2Ac(oyl-L-Ala-γ-D-Glu-L-Lys-D-Ala-D-Ala)]n ligase (ADP-forming)
Comments: This enzyme forms part of the peptidoglycan assembly pathway of Gram-positive bacteria grown in medium containing D-Asp. Normally, the side chains the acylate the 6-amino group of the L-lysine residue contain L-Ala-L-Ala but these amino acids are replaced by D-Asp when D-Asp is included in the medium. Hybrid chains containing L-Ala-D-Asp, L-Ala-L-Ala-D-Asp or D-Asp-L-Ala are not formed [4]. The enzyme belongs in the ATP-grasp protein superfamily [3,4]. The enzyme is highly specific for D-aspartate, as L-aspartate, D-glutamate, D-alanine, D-iso-asparagine and D-malic acid are not substrates [4]. In Enterococcus faecium, the substrate D-aspartate is produced by EC 5.1.1.13, aspartate racemase [4]
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc
References:
1.  Staudenbauer, W. and Strominger, J.L. Activation of D-aspartic acid for incorporation into peptidoglycan. J. Biol. Chem. 247 (1972) 5095–5102. [PMID: 4262567]
2.  Staudenbauer, W., Willoughby, E. and Strominger, J.L. Further studies of the D-aspartic acid-activating enzyme of Streptococcus faecalis and its attachment to the membrane. J. Biol. Chem. 247 (1972) 5289–5296. [PMID: 4626717]
3.  Galperin, M.Y. and Koonin, E.V. A diverse superfamily of enzymes with ATP-dependent carboxylate-amine/thiol ligase activity. Protein Sci. 6 (1997) 2639–2643. [DOI] [PMID: 9416615]
4.  Bellais, S., Arthur, M., Dubost, L., Hugonnet, J.E., Gutmann, L., van Heijenoort, J., Legrand, R., Brouard, J.P., Rice, L. and Mainardi, J.L. Aslfm, the D-aspartate ligase responsible for the addition of D-aspartic acid onto the peptidoglycan precursor of Enterococcus faecium. J. Biol. Chem. 281 (2006) 11586–11594. [DOI] [PMID: 16510449]
[EC 6.3.1.12 created 2006]
 
 
EC 2.4.1.223     Relevance: 56.8%
Accepted name: glucuronosyl-galactosyl-proteoglycan 4-α-N-acetylglucosaminyltransferase
Reaction: UDP-N-acetyl-α-D-glucosamine + [protein]-3-O-(β-D-GlcA-(1→3)-β-D-Gal-(1→3)-β-D-Gal-(1→4)-β-D-Xyl)-L-serine = UDP + [protein]-3-O-(α-D-GlcNAc-(1→4)-β-D-GlcA-(1→3)-β-D-Gal-(1→3)-β-D-Gal-(1→4)-β-D-Xyl)-L-serine
For diagram of heparan biosynthesis (later stages), click here
Glossary: [protein]-3-O-(β-D-GlcA-(1→3)-β-D-Gal-(1→3)-β-D-Gal-(1→4)-β-D-Xyl)-L-serine = [protein]-3-O-(β-D-glucuronosyl-(1→3)-β-D-galactosyl-(1→3)-β-D-galactosyl-(1→4)-β-D-xylosyl)-L-serine
Other name(s): α-N-acetylglucosaminyltransferase I; α1,4-N-acetylglucosaminyltransferase; glucuronosylgalactosyl-proteoglycan 4-α-N-acetylglucosaminyltransferase; UDP-N-acetyl-D-glucosamine:β-D-glucuronosyl-(1→3)-β-D-galactosyl-(1→3)-β-D-galactosyl-(1→4)-β-D-xylosyl-proteoglycan 4IV-α-N-acetyl-D-glucosaminyltransferase; glucuronyl-galactosyl-proteoglycan 4-α-N-acetylglucosaminyltransferase
Systematic name: UDP-N-acetyl-α-D-glucosamine:[protein]-3-O-(β-D-GlcA-(1→3)-β-D-Gal-(1→3)-β-D-Gal-(1→4)-β-D-Xyl)-L-serine 4IV-α-N-acetyl-D-glucosaminyltransferase (configuration-retaining)
Comments: Enzyme involved in the initiation of heparin and heparan sulfate synthesis, transferring GlcNAc to the (GlcA-Gal-Gal-Xyl-)Ser core. Apparently products of both the human EXTL2 and EXTL3 genes can catalyse this reaction. In Caenorhabditis elegans, the product of the rib-2 gene displays this activity as well as that of EC 2.4.1.224, glucuronosyl-N-acetylglucosaminyl-proteoglycan 4-α-N-acetylglucosaminyltransferase. For explanation of the use of a superscript in the systematic name, see 2-Carb-37.2.
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc, PDB, CAS registry number: 179241-74-8
References:
1.  Kitagawa, H., Shimakawa, H. and Sugahara, K. The tumor suppressor EXT-like gene EXTL2 encodes an α1,4-N-acetylhexosaminyltransferase that transfers N-acetylgalactosamine and N-acetylglucosamine to the common glycosaminoglycan-protein linkage region. The key enzyme for the chain initiation of heparan sulfate. J. Biol. Chem. 274 (1999) 13933–13937. [DOI] [PMID: 10318803]
2.  Kitagawa, H., Egusa, N., Tamura, J.I., Kusche-Gullberg, M., Lindahl, U. and Sugahara, K. rib-2, a Caenorhabditis elegans homolog of the human tumor suppressor EXT genes encodes a novel α1,4-N-acetylglucosaminyltransferase involved in the biosynthetic initiation and elongation of heparan sulfate. J. Biol. Chem. 276 (2001) 4834–4838. [DOI] [PMID: 11121397]
[EC 2.4.1.223 created 2002, modified 2016]
 
 
EC 3.2.1.132     Relevance: 56.3%
Accepted name: chitosanase
Reaction: Endohydrolysis of β-(1→4)-linkages between D-glucosamine residues in a partly acetylated chitosan
Systematic name: chitosan N-acetylglucosaminohydrolase
Comments: A whole spectrum of chitosanases are now known (for more details, see http://rbrzezinski.recherche.usherbrooke.ca/). They can hydrolyse various types of links in chitosan. The only constant property is the endohydrolysis of GlcN-GlcN links, which is common to all known chitosanases. One known chitosanase is limited to this link recognition [4], while the majority can also recognize GlcN-GlcNAc links or GlcNAc-GlcN links but not both. They also do not recognize GlcNAc-GlcNAc links in partly acetylated chitosan.
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc, PDB, CAS registry number: 51570-20-8
References:
1.  Fenton, D.M. and Eveleigh, D.E. Purification and mode of action of a chitosanase from Penicillium islandicum. J. Gen. Microbiol. 126 (1981) 151–165.
2.  Saito, J.-I., Kita, A., Higuchi, Y., Nagata, Y., Ando, A. and Miki, K. Crystal structure of chitosanase from Bacillus circulans MH-K1 at 1.6-Å resolution and its substrate recognition mechanism. J. Biol. Chem. 274 (1999) 30818–30825. [DOI] [PMID: 10521473]
3.  Izume, M., Nagae, S., Kawagishi, H., Mitsutomi, M. and Ohtakara, A. Action pattern of Bacillus sp. No. 7-M chitosanase on partially N-acetylated chitosan. Biosci. Biotechnol. Biochem. 56 (1992) 448–453. [DOI] [PMID: 1368330]
4.  Marcotte, E.M., Monzingo, A.F., Ernst, S.R., Brzezinski, R. and Robertus, J.D. X-ray structure of an anti-fungal chitosanase from Streptomyces N174. Nat. Struct. Biol. 3 (1996) 155–162. [PMID: 8564542]
[EC 3.2.1.132 created 1990, modified 2004]
 
 
EC 3.2.1.209     Relevance: 55%
Accepted name: endoplasmic reticulum Man9GlcNAc2 1,2-α-mannosidase
Reaction: Man9GlcNAc2-[protein] + H2O = Man8GlcNAc2-[protein] (isomer 8A1,2,3B1,3) + D-mannopyranose
Glossary: Man9GlcNAc2-[protein] = {α-D-Man-(1→2)-α-D-Man-(1→2)-α-D-Man-(1→3)-[α-D-Man-(1→2)-α-D-Man-(1→3)-[α-D-Man-(1→2)-α-D-Man-(1→6)]-α-D-Man-(1→6)]-β-D-Man-(1→4)-β-D-GlcNAc-(1→4)-α-D-GlcNAc}-N-Asn-[protein]
Man8GlcNAc2-[protein] (isomer 8A1,2,3B1,3) = {α-D-Man-(1→2)-α-D-Man-(1→2)-α-D-Man-(1→3)-[α-D-Man-(1→3)-[α-D-Man-(1→2)-α-D-Man-(1→6)]-α-D-Man-(1→6)]-β-D-Man-(1→4)-β-D-GlcNAc-(1→4)-α-D-GlcNAc}-N-Asn-[protein]
Other name(s): MAN1B1 (gene name); MNS1 (gene name); MNS3 (gene name)
Systematic name: Man9GlcNAc2-[protein]2-α-mannohydrolase (configuration-inverting)
Comments: The enzyme, located in the endoplasmic reticulum, primarily trims a single α-1,2-linked mannose residue from Man9GlcNAc2 to produce Man8GlcNAc2 isomer 8A1,2,3B1,3 (the names of the isomers listed here are based on a nomenclature system proposed by Prien et al [7]). The removal of the single mannosyl residue occurs in all eukaryotes as part of the processing of N-glycosylated proteins, and is absolutely essential for further elongation of the outer chain of properly-folded N-glycosylated proteins in yeast. In addition, the enzyme is involved in glycoprotein quality control at the ER quality control compartment (ERQC), helping to target misfolded glycoproteins for degradation. When present at very high concentrations in the ERQC, the enzyme can trim the carbohydrate chain further to Man(5-6)GlcNAc2.
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc
References:
1.  Jelinek-Kelly, S. and Herscovics, A. Glycoprotein biosynthesis in Saccharomyces cerevisiae. Purification of the α-mannosidase which removes one specific mannose residue from Man9GlcNAc. J. Biol. Chem. 263 (1988) 14757–14763. [PMID: 3049586]
2.  Ziegler, F.D. and Trimble, R.B. Glycoprotein biosynthesis in yeast: purification and characterization of the endoplasmic reticulum Man9 processing α-mannosidase. Glycobiology 1 (1991) 605–614. [PMID: 1822240]
3.  Gonzalez, D.S., Karaveg, K., Vandersall-Nairn, A.S., Lal, A. and Moremen, K.W. Identification, expression, and characterization of a cDNA encoding human endoplasmic reticulum mannosidase I, the enzyme that catalyzes the first mannose trimming step in mammalian Asn-linked oligosaccharide biosynthesis. J. Biol. Chem. 274 (1999) 21375–21386. [PMID: 10409699]
4.  Herscovics, A., Romero, P.A. and Tremblay, L.O. The specificity of the yeast and human class I ER α 1,2-mannosidases involved in ER quality control is not as strict previously reported. Glycobiology 12 (2002) 14G–15G. [PMID: 12090241]
5.  Avezov, E., Frenkel, Z., Ehrlich, M., Herscovics, A. and Lederkremer, G.Z. Endoplasmic reticulum (ER) mannosidase I is compartmentalized and required for N-glycan trimming to Man5-6GlcNAc2 in glycoprotein ER-associated degradation. Mol. Biol. Cell 19 (2008) 216–225. [PMID: 18003979]
6.  Liebminger, E., Huttner, S., Vavra, U., Fischl, R., Schoberer, J., Grass, J., Blaukopf, C., Seifert, G.J., Altmann, F., Mach, L. and Strasser, R. Class I α-mannosidases are required for N-glycan processing and root development in Arabidopsis thaliana. Plant Cell 21 (2009) 3850–3867. [PMID: 20023195]
7.  Prien, J.M., Ashline, D.J., Lapadula, A.J., Zhang, H. and Reinhold, V.N. The high mannose glycans from bovine ribonuclease B isomer characterization by ion trap MS. J. Am. Soc. Mass Spectrom. 20 (2009) 539–556. [DOI] [PMID: 19181540]
[EC 3.2.1.209 created 2019]
 
 
EC 2.4.1.371     Relevance: 54.7%
Accepted name: polymannosyl GlcNAc-diphospho-ditrans,octacis-undecaprenol 2,3-α-mannosylpolymerase
Reaction: (1) 2 GDP-α-D-mannose + [α-D-Man-(1→3)-α-D-Man-(1→3)-α-D-Man-(1→2)-α-D-Man-(1→2)]n-α-D-Man-(1→3)-α-D-Man-(1→3)-α-D-Man-(1→3)-α-D-GlcNAc-diphospho-ditrans,octacis-undecaprenol = 2 GDP + α-D-Man-(1→2)-α-D-Man-(1→2)-[α-D-Man-(1→3)-α-D-Man-(1→3)-α-D-Man-(1→2)-α-D-Man-(1→2)]n-α-D-Man-(1→3)-α-D-Man-(1→3)-α-D-Man-(1→3)-α-D-GlcNAc-diphospho-ditrans,octacis-undecaprenol
(2) 2 GDP-α-D-mannose + α-D-Man-(1→2)-α-D-Man-(1→2)-[α-D-Man-(1→3)-α-D-Man-(1→3)-α-D-Man-(1→2)-α-D-Man-(1→2)]n-α-D-Man-(1→3)-α-D-Man-(1→3)-α-D-Man-(1→3)-α-D-GlcNAc-diphospho-ditrans,octacis-undecaprenol = 2 GDP + [α-D-Man-(1→3)-α-D-Man-(1→3)-α-D-Man-(1→2)-α-D-Man-(1→2)]n+1-α-D-Man-(1→3)-α-D-Man-(1→3)-α-D-Man-(1→3)-α-D-GlcNAc-diphospho-ditrans,octacis-undecaprenol
Other name(s): WbdA
Systematic name: GDP-α-D-mannose:α-D-Man-(1→2)-α-D-Man-(1→2)-[α-D-Man-(1→3)-α-D-Man-(1→3)-α-D-Man-(1→2)-α-D-Man-(1→2)]n-α-D-Man-(1→3)-α-D-Man-(1→3)-α-D-Man-(1→3)-α-D-GlcNAc-diphospho-ditrans,octacis-undecaprenol 2,3-α-mannosyltransferase (configuration-retaining)
Comments: The enzyme is involved in the biosynthesis of polymannose O-polysaccharide in the outer leaflet of the membrane of Escherichia coli serotype O9a. The enzymes consists of two domains that are responsible for the 1→2 and 1→3 linkages, respectively.
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc
References:
1.  Greenfield, L.K., Richards, M.R., Li, J., Wakarchuk, W.W., Lowary, T.L. and Whitfield, C. Biosynthesis of the polymannose lipopolysaccharide O-antigens from Escherichia coli serotypes O8 and O9a requires a unique combination of single- and multiple-active site mannosyltransferases. J. Biol. Chem. 287 (2012) 35078–35091. [DOI] [PMID: 22875852]
2.  Greenfield, L.K., Richards, M.R., Vinogradov, E., Wakarchuk, W.W., Lowary, T.L. and Whitfield, C. Domain organization of the polymerizing mannosyltransferases involved in synthesis of the Escherichia coli O8 and O9a lipopolysaccharide O-antigens. J. Biol. Chem. 287 (2012) 38135–38149. [PMID: 22989876]
3.  Liston, S.D., Clarke, B.R., Greenfield, L.K., Richards, M.R., Lowary, T.L. and Whitfield, C. Domain interactions control complex formation and polymerase specificity in the biosynthesis of the Escherichia coli O9a antigen. J. Biol. Chem. 290 (2015) 1075–1085. [DOI] [PMID: 25422321]
[EC 2.4.1.371 created 2019]
 
 
EC 2.7.1.181     Relevance: 53%
Accepted name: polymannosyl GlcNAc-diphospho-ditrans,octacis-undecaprenol kinase
Reaction: ATP + α-D-Man-(1→2)-α-D-Man-(1→2)-[α-D-Man-(1→3)-α-D-Man-(1→3)-α-D-Man-(1→2)-α-D-Man-(1→2)]n-α-D-Man-(1→3)-α-D-Man-(1→3)-α-D-Man-(1→3)-α-D-GlcNAc-diphospho-ditrans,octacis-undecaprenol = ADP + 3-O-phospho-α-D-Man-(1→2)-α-D-Man-(1→2)-[α-D-Man-(1→3)-α-D-Man-(1→3)-α-D-Man-(1→2)-α-D-Man-(1→2)]n-α-D-Man-(1→3)-α-D-Man-(1→3)-α-D-Man-(1→3)-α-D-GlcNAc-diphospho-ditrans,octacis-undecaprenol
Other name(s): WbdD; ATP:α-D-Man-(1→2)-α-D-Man-(1→2)-α-D-Man-(1→3)-α-D-Man-(1→3)-[α-D-Man-(1→2)-α-D-Man-(1→2)-α-D-Man-(1→3)-α-D-Man-(1→3)]n-α-D-Man-(1→3)-α-D-Man-(1→3)-α-D-GlcNAc-diphospho-ditrans,octacis-undecaprenol 3-phosphotransferase
Systematic name: ATP:α-D-Man-(1→2)-α-D-Man-(1→2)-[α-D-Man-(1→3)-α-D-Man-(1→3)-α-D-Man-(1→2)-α-D-Man-(1→2)]n-α-D-Man-(1→3)-α-D-Man-(1→3)-α-D-Man-(1→3)-α-D-GlcNAc-diphospho-ditrans,octacis-undecaprenol 3-phosphotransferase
Comments: The enzyme is involved in the biosynthesis of the polymannose O-polysaccharide in the outer leaflet of the membrane of Escherichia coli serotype O9a. O-Polysaccharide structures vary extensively because of differences in the number and type of sugars in the repeat unit. The dual kinase/methylase WbdD also catalyses the methylation of 3-phospho-α-D-Man-(1→2)-α-D-Man-(1→2)-[α-D-Man-(1→3)-α-D-Man-(1→3)-α-D-Man-(1→2)-α-D-Man-(1→2)]n-α-D-Man-(1→3)-α-D-Man-(1→3)-α-D-Man-(1→3)-α-D-GlcNAc-diphospho-ditrans,octacis-undecaprenol (cf. EC 2.1.1.294, 3-O-phospho-polymannosyl GlcNAc-diphospho-ditrans,octacis-undecaprenol 3-phospho-methyltransferase).
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc
References:
1.  Clarke, B.R., Cuthbertson, L. and Whitfield, C. Nonreducing terminal modifications determine the chain length of polymannose O antigens of Escherichia coli and couple chain termination to polymer export via an ATP-binding cassette transporter. J. Biol. Chem. 279 (2004) 35709–35718. [DOI] [PMID: 15184370]
2.  Clarke, B.R., Greenfield, L.K., Bouwman, C. and Whitfield, C. Coordination of polymerization, chain termination, and export in assembly of the Escherichia coli lipopolysaccharide O9a antigen in an ATP-binding cassette transporter-dependent pathway. J. Biol. Chem. 284 (2009) 30662–30672. [DOI] [PMID: 19734145]
3.  Clarke, B.R., Richards, M.R., Greenfield, L.K., Hou, D., Lowary, T.L. and Whitfield, C. In vitro reconstruction of the chain termination reaction in biosynthesis of the Escherichia coli O9a O-polysaccharide: the chain-length regulator, WbdD, catalyzes the addition of methyl phosphate to the non-reducing terminus of the growing glycan. J. Biol. Chem. 286 (2011) 41391–41401. [DOI] [PMID: 21990359]
4.  Liston, S.D., Clarke, B.R., Greenfield, L.K., Richards, M.R., Lowary, T.L. and Whitfield, C. Domain interactions control complex formation and polymerase specificity in the biosynthesis of the Escherichia coli O9a antigen. J. Biol. Chem. 290 (2015) 1075–1085. [DOI] [PMID: 25422321]
[EC 2.7.1.181 created 2014, modified 2017]
 
 
EC 2.4.1.343     Relevance: 51.7%
Accepted name: UDP-Gal:α-D-GlcNAc-diphosphoundecaprenol α-1,3-galactosyltransferase
Reaction: UDP-α-D-galactose + N-acetyl-α-D-glucosaminyl-diphospho-ditrans,octacis-undecaprenol = UDP + α-D-Gal-(1→3)-α-D-GlcNAc-diphospho-ditrans,octacis-undecaprenol
Other name(s): wclR (gene name)
Systematic name: UDP-α-D-galactose:N-acetyl-α-D-glucosaminyl-diphospho-ditrans,octacis-undecaprenol 3-α-galactosyltransferase (configuration-retaining)
Comments: The enzyme is involved in the the biosynthesis of the O-antigen repeating unit of Escherichia coli O3. Requires a divalent metal ion (Mn2+, Mg2+ or Fe2+). cf. EC 2.4.1.303, UDP-Gal:α-D-GlcNAc-diphosphoundecaprenol β-1,3-galactosyltransferase.
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc
References:
1.  Chen, C., Liu, B., Xu, Y., Utkina, N., Zhou, D., Danilov, L., Torgov, V., Veselovsky, V. and Feng, L. Biochemical characterization of the novel α-1, 3-galactosyltransferase WclR from Escherichia coli O3. Carbohydr. Res. 430 (2016) 36–43. [DOI] [PMID: 27196310]
[EC 2.4.1.343 created 2017]
 
 


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