The Enzyme Database

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EC 2.4.1.25     
Accepted name: 4-α-glucanotransferase
Reaction: Transfers a segment of a (1→4)-α-D-glucan to a new position in an acceptor, which may be glucose or a (1→4)-α-D-glucan
Other name(s): disproportionating enzyme; dextrin glycosyltransferase; D-enzyme; debranching enzyme maltodextrin glycosyltransferase; amylomaltase; dextrin transglycosylase; 1,4-α-D-glucan:1,4-α-D-glucan 4-α-D-glycosyltransferase
Systematic name: (1→4)-α-D-glucan:(1→4)-α-D-glucan 4-α-D-glycosyltransferase
Comments: This entry covers the former separate entry for EC 2.4.1.3 (amylomaltase). The plant enzyme has been termed D-enzyme. An enzymic activity of this nature forms part of the mammalian and yeast glycogen debranching system (see EC 3.2.1.33 amylo-α-1,6-glucosidase).
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc, PDB, CAS registry number: 9032-09-1
References:
1.  Hehre, E.J. Enzymic synthesis of polysaccharides: a biological type of polymerization. Adv. Enzymol. Relat. Subj. Biochem. 11 (1951) 297–337. [PMID: 24540594]
2.  Lukomskaya, I.S. Synthesis of oligosaccharides with α-1,6-bonds by enzyme preparations from liver and muscle. Dokl. Akad. Nauk S.S.S.R. 129 (1959) 1172–1175. (in Russian)
3.  Pazur, J.H. and Okada, S. The isolation and mode of action of a bacterial glucanosyltransferase. J. Biol. Chem. 243 (1968) 4732–4738. [PMID: 4972097]
4.  Walker, G.J. and Whelan, W.J. Synthesis of amylose by potato D-enzyme. Nature 183 (1959) 46. [PMID: 13622683]
5.  Whelan, W.H. Enzymic explorations of the structures of starch and glycogen. Biochem. J. 122 (1971) 609–622. [PMID: 5001952]
[EC 2.4.1.25 created 1965 (EC 2.4.1.3 created 1961, incorporated 1972)]
 
 
EC 2.4.1.250     
Accepted name: D-inositol-3-phosphate glycosyltransferase
Reaction: UDP-N-acetyl-α-D-glucosamine + 1D-myo-inositol 3-phosphate = 1-O-(2-acetamido-2-deoxy-α-D-glucopyranosyl)-1D-myo-inositol 3-phosphate + UDP
For diagram of mycothiol biosynthesis, click here
Glossary: mycothiol = 1-O-[2-(N2-acetyl-L-cysteinamido)-2-deoxy-α-D-glucopyranosyl]-1D-myo-inositol
Other name(s): mycothiol glycosyltransferases; MshA; UDP-N-acetyl-D-glucosamine:1D-myo-inositol 3-phosphate α-D-glycosyltransferase
Systematic name: UDP-N-acetyl-α-D-glucosamine:1D-myo-inositol 3-phosphate α-D-glycosyltransferase (configuration-retaining)
Comments: The enzyme, which belongs to the GT-B fold superfamily, catalyses the first dedicated reaction in the biosynthesis of mycothiol [1]. The substrate was initially believed to be inositol, but eventually shown to be D-myo-inositol 3-phosphate [2]. A substantial conformational change occurs upon UDP binding, which generates the binding site for D-myo-inositol 3-phosphate [3].
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc
References:
1.  Newton, G.L., Koledin, T., Gorovitz, B., Rawat, M., Fahey, R.C. and Av-Gay, Y. The glycosyltransferase gene encoding the enzyme catalyzing the first step of mycothiol biosynthesis (mshA). J. Bacteriol. 185 (2003) 3476–3479. [DOI] [PMID: 12754249]
2.  Newton, G.L., Ta, P., Bzymek, K.P. and Fahey, R.C. Biochemistry of the initial steps of mycothiol biosynthesis. J. Biol. Chem. 281 (2006) 33910–33920. [DOI] [PMID: 16940050]
3.  Vetting, M.W., Frantom, P.A. and Blanchard, J.S. Structural and enzymatic analysis of MshA from Corynebacterium glutamicum: substrate-assisted catalysis. J. Biol. Chem. 283 (2008) 15834–15844. [DOI] [PMID: 18390549]
[EC 2.4.1.250 created 2010]
 
 
EC 2.4.1.251     
Accepted name: GlcA-β-(1→2)-D-Man-α-(1→3)-D-Glc-β-(1→4)-D-Glc-α-1-diphospho-ditrans,octacis-undecaprenol 4-β-mannosyltransferase
Reaction: GDP-mannose + GlcA-β-(1→2)-D-Man-α-(1→3)-D-Glc-β-(1→4)-D-Glc-α-1-diphospho-ditrans,octacis-undecaprenol = GDP + D-Man-β-(1→4)- GlcA-β-(1→2)-D-Man-α-(1→3)-D-Glc-β-(1→4)-D-Glc-α-1-diphospho-ditrans,octacis-undecaprenol
For diagram of xanthan biosynthesis, click here
Other name(s): GumI
Systematic name: GDP-mannose:GlcA-β-(1→2)-D-Man-α-(1→3)-D-Glc-β-(1→4)-D-Glc-α-1-diphospho-ditrans,octacis-undecaprenol 4-β-mannosyltransferase
Comments: The enzyme is involved in the biosynthesis of the exopolysaccharide xanthan.
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc
References:
1.  Katzen, F., Ferreiro, D.U., Oddo, C.G., Ielmini, M.V., Becker, A., Puhler, A. and Ielpi, L. Xanthomonas campestris pv. campestris gum mutants: effects on xanthan biosynthesis and plant virulence. J. Bacteriol. 180 (1998) 1607–1617. [PMID: 9537354]
2.  Ielpi, L., Couso, R.O. and Dankert, M.A. Sequential assembly and polymerization of the polyprenol-linked pentasaccharide repeating unit of the xanthan polysaccharide in Xanthomonas campestris. J. Bacteriol. 175 (1993) 2490–2500. [DOI] [PMID: 7683019]
3.  Kim, S.Y., Kim, J.G., Lee, B.M. and Cho, J.Y. Mutational analysis of the gum gene cluster required for xanthan biosynthesis in Xanthomonas oryzae pv oryzae. Biotechnol. Lett. 31 (2009) 265–270. [DOI] [PMID: 18854951]
[EC 2.4.1.251 created 2011]
 
 
EC 2.4.1.252     
Accepted name: GDP-mannose:cellobiosyl-diphosphopolyprenol α-mannosyltransferase
Reaction: GDP-mannose + D-Glc-β-(1→4)-Glc-α-1-diphospho-ditrans,octacis-undecaprenol = GDP + D-Man-α-(1→3)-D-Glc-β-(1→4)-D-Glc-α-1-diphospho-ditrans,octacis-undecaprenol
For diagram of xanthan biosynthesis, click here
Other name(s): GumH; AceA; α1,3-mannosyltransferase AceA
Systematic name: GDP-mannose:D-Glc-β-(1→4)-Glc-α-1-diphospho-ditrans,octacis-undecaprenol 3-α-mannosyltransferase
Comments: In the bacterium Gluconacetobacter xylinus (previously known as Acetobacter xylinum) the enzyme is involved in the biosynthesis of the exopolysaccharide acetan [1]. In Xanthomonas campestris the enzyme is involved in the biosynthesis of the exopolysaccharide xanthan [5].
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc
References:
1.  Geremia, R.A., Roux, M., Ferreiro, D.U., Dauphin-Dubois, R., Lellouch, A.C. and Ielpi, L. Expression and biochemical characterisation of recombinant AceA, a bacterial α-mannosyltransferase. Mol. Gen. Genet. 261 (1999) 933–940. [PMID: 10485283]
2.  Abdian, P.L., Lellouch, A.C., Gautier, C., Ielpi, L. and Geremia, R.A. Identification of essential amino acids in the bacterial α-mannosyltransferase aceA. J. Biol. Chem. 275 (2000) 40568–40575. [DOI] [PMID: 11001941]
3.  Petroni, E.A. and Ielpi, L. Isolation and nucleotide sequence of the GDP-mannose:cellobiosyl-diphosphopolyprenol α-mannosyltransferase gene from Acetobacter xylinum. J. Bacteriol. 178 (1996) 4814–4821. [DOI] [PMID: 8759843]
4.  Lellouch, A.C., Watt, G.M., Geremia, R.A. and Flitsch, S.L. Phytanyl-pyrophosphate-linked substrate for a bacterial α-mannosyltransferase. Biochem. Biophys. Res. Commun. 272 (2000) 290–292. [DOI] [PMID: 10872841]
5.  Katzen, F., Ferreiro, D.U., Oddo, C.G., Ielmini, M.V., Becker, A., Puhler, A. and Ielpi, L. Xanthomonas campestris pv. campestris gum mutants: effects on xanthan biosynthesis and plant virulence. J. Bacteriol. 180 (1998) 1607–1617. [PMID: 9537354]
[EC 2.4.1.252 created 2011]
 
 
EC 2.4.1.253     
Accepted name: baicalein 7-O-glucuronosyltransferase
Reaction: UDP-D-glucuronate + baicalein = UDP + baicalin
Glossary: baicalin = 5,6,7-trihydroxyflavone-7-O-β-D-glucuronate = 5,6-dihydroxy-4-oxo-2-phenyl-4H-chromen-7-yl β-D-glucupyranosiduronic acid
baicalein = 5,6,7-trihydroxyflavone = 5,6,7-trihydroxy-2-phenyl-4H-chromen-4-one
wogonin = 5,7-dihydroxy-8-methoxyflavone = 5,7-dihydroxy-8-methoxy-2-phenyl-4H-chromen-4-one
scutellarein = 4,5,6,7-tetrahydroxyflavone-7-O-β-D-glucoronate = 5,6,7-trihydroxy-2-(4-hydroxyphenyl)chromen-4-one
Other name(s): UBGAT
Systematic name: UDP-D-glucuronate:5,6,7-trihydroxyflavone 7-O-glucuronosyltransferase
Comments: The enzyme is specific for UDP-D-glucuronate as a sugar donor and flavones with substitution ortho- to the 7-OH group such as baicalein (6-OH), scutellarein (6-OH) and wogonin (8-OMe).
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc
References:
1.  Nagashima, S., Hirotani, M. and Yoshikawa, T. Purification and characterization of UDP-glucuronate: baicalein 7-O-glucuronosyltransferase from Scutellaria baicalensis Georgi. cell suspension cultures. Phytochemistry 53 (2000) 533–538. [DOI] [PMID: 10724177]
[EC 2.4.1.253 created 2011]
 
 
EC 2.4.1.254     
Accepted name: cyanidin-3-O-glucoside 2′′-O-glucuronosyltransferase
Reaction: UDP-α-D-glucuronate + cyanidin 3-O-β-D-glucoside = UDP + cyanidin 3-O-(2-O-β-D-glucuronosyl)-β-D-glucoside
Glossary: cyanidin = 3,3′,4′,5,7-pentahydroxyflavylium
Other name(s): BpUGT94B1; UDP-glucuronic acid:anthocyanin glucuronosyltransferase; UDP-glucuronic acid:anthocyanidin 3-glucoside 2′-O-β-glucuronosyltransferase; BpUGAT; UDP-D-glucuronate:cyanidin-3-O-β-glucoside 2-O-β-glucuronosyltransferase
Systematic name: UDP-α-D-glucuronate:cyanidin-3-O-β-D-glucoside 2-O-β-D-glucuronosyltransferase
Comments: The enzyme is highly specific for cyanidin 3-O-glucosides and UDP-α-D-glucuronate. Involved in the production of glucuronosylated anthocyanins that are the origin of the red coloration of flowers of Bellis perennis [1].
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc
References:
1.  Sawada, S., Suzuki, H., Ichimaida, F., Yamaguchi, M.A., Iwashita, T., Fukui, Y., Hemmi, H., Nishino, T. and Nakayama, T. UDP-glucuronic acid:anthocyanin glucuronosyltransferase from red daisy (Bellis perennis) flowers. Enzymology and phylogenetics of a novel glucuronosyltransferase involved in flower pigment biosynthesis. J. Biol. Chem. 280 (2005) 899–906. [DOI] [PMID: 15509561]
2.  Osmani, S.A., Bak, S., Imberty, A., Olsen, C.E. and Møller, B.L. Catalytic key amino acids and UDP-sugar donor specificity of a plant glucuronosyltransferase, UGT94B1: molecular modeling substantiated by site-specific mutagenesis and biochemical analyses. Plant Physiol. 148 (2008) 1295–1308. [DOI] [PMID: 18829982]
[EC 2.4.1.254 created 2011]
 
 
EC 2.4.1.255     
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 2.4.1.256     
Accepted name: dolichyl-P-Glc:Glc2Man9GlcNAc2-PP-dolichol α-1,2-glucosyltransferase
Reaction: 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 = D-Glc-α-(1→2)-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 + dolichyl phosphate
For diagram of dolichyltetradecasaccharide biosynthesis, click here
Other name(s): ALG10; Dol-P-Glc:Glc2Man9GlcNAc2-PP-Dol α-1,2-glucosyltransferase
Systematic name: 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
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 2.4.1.257     
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 2.4.1.258     
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     
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]
 
 


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