EC 3.2.1.15     
Accepted name: endo-polygalacturonase
Reaction: (1,4-α-D-galacturonosyl)n+m + H2O = (1,4-α-D-galacturonosyl)n + (1,4-α-D-galacturonosyl)m
Other name(s): pectin depolymerase (ambiguous); pectinase (ambiguous); endopolygalacturonase; pectolase (ambiguous); pectin hydrolase (ambiguous); pectin polygalacturonase (ambiguous); polygalacturonase (ambiguous); poly-α-1,4-galacturonide glycanohydrolase (ambiguous); endogalacturonase; endo-D-galacturonase; poly(1,4-α-D-galacturonide) glycanohydrolase (ambiguous)
Systematic name: (1→4)-α-D-galacturonan glycanohydrolase (endo-cleaving)
Comments: The enzyme catalyses the random hydrolysis of (1→4)-α-D-galactosiduronic linkages in pectate and other galacturonans. Different forms of the enzyme have different tolerances to methyl esterification of the substrate.
References:
1.  Lineweaver, H. and Jansen, E.F. Pectic enzymes. Adv. Enzymol. Relat. Subj. Biochem. 11 (1951) 267–295.
2.  McCready, R.M. and Seegmiller, C.G. Action of pectic enzymes on oligogalacturonic acids and some of their derivatives. Arch. Biochem. Biophys. 50 (1954) 440–450. [PMID: 13159344]
3.  Phaff, H.J. and Demain, A.L. The unienzymatic nature of yeast polygalacturonase. J. Biol. Chem. 218 (1956) 875–884. [PMID: 13295238]
4.  Deuel, H. and Stutz, E. Pectic substances and pectic enzymes. Adv. Enzymol. Relat. Areas Mol. Biol. 20 (1958) 341–382. [PMID: 13605988]
5.  Mill, P.J. and Tuttobello, R. The pectic enzymes of Aspergillus niger. 2. Endopolygalacturonase. Biochem. J. 79 (1961) 57–64. [PMID: 13770689]
[EC 3.2.1.15 created 1961, modified 2019]
 
 
EC 3.2.1.150     
Accepted name: oligoxyloglucan reducing-end-specific cellobiohydrolase
Reaction: Hydrolysis of cellobiose from the reducing end of xyloglucans consisting of a (1→4)-β-linked glucan carrying α-D-xylosyl groups on O-6 of the glucose residues. To be a substrate, the first residue must be unsubstituted, the second residue may bear a xylosyl group, whether further glycosylated or not, and the third residue, which becomes the new terminus by the action of the enzyme, is preferably xylosylated, but this xylose residue must not be further substituted.
Systematic name: oligoxyloglucan reducing-end cellobiohydrolase
Comments: The enzyme is found in the fungus Geotrichum sp. M128. The substrate is a hemicellulose found in plant cell walls.
References:
1.  Yaoi, K. and Mitsuishi, Y. Purification, characterization, cloning, and expression of a novel xyloglucan-specific glycosidase, oligoxyloglucan reducing end-specific cellobiohydrolase. J. Biol. Chem. 277 (2002) 48276–48281. [PMID: 12374797]
[EC 3.2.1.150 created 2003]
 
 
EC 3.2.1.151     
Accepted name: xyloglucan-specific endo-β-1,4-glucanase
Reaction: xyloglucan + H2O = xyloglucan oligosaccharides
Other name(s): XEG; xyloglucan endo-β-1,4-glucanase; xyloglucanase; xyloglucanendohydrolase; XH; 1,4-β-D-glucan glucanohydrolase
Systematic name: [(1→6)-α-D-xylo]-(1→4)-β-D-glucan glucanohydrolase
Comments: The enzyme from Aspergillus aculeatus is specific for xyloglucan and does not hydrolyse other cell-wall components. The reaction involves endohydrolysis of 1,4-β-D-glucosidic linkages in xyloglucan with retention of the β-configuration of the glycosyl residues.
References:
1.  Pauly, M., Andersen, L.N., Kaupinnen, S., Kofod, L.V., York, W.S., Albersheim, P. and Darvill, A. A xyloglucan specific endo-β-1,4-glucanase from Aspergillus aculeatus: expression cloning in yeast, purification and characterization of the recombinant enzyme. Glycobiology 9 (1999) 93–100. [PMID: 9884411]
2.  Grishutin, S.G., Gusakov, A.V., Markov, A.V., Ustinov, B.B., Semenova, M.V. and Sinitsyn, A.P. Specific xyloglucanases as a new class of polysaccharide-degrading enzymes. Biochim. Biophys. Acta 1674 (2004) 268–281. [PMID: 15541296]
[EC 3.2.1.151 created 2003]
 
 
EC 3.2.1.152     
Accepted name: mannosylglycoprotein endo-β-mannosidase
Reaction: Hydrolysis of the α-D-mannosyl-(1→6)-β-D-mannosyl-(1→4)-N-acetyl-β-D-glucosaminyl-(1→4)-N-acetyl-β-D-glucosaminyl sequence of glycoprotein to α-D-mannosyl-(1→6)-D-mannose and N-acetyl-β-D-glucosaminyl-(1→4)-N-acetyl-β-D-glucosaminyl sequences
Other name(s): endo-β-mannosidase
Comments: The substrate group is a substituent on N-4 of an asparagine residue in the glycoprotein. The mannose residue at the non-reducing end of the sequence may carry further α-D-mannosyl groups on O-3 or O-6, but such a substituent on O-3 of the β-D-mannosyl group prevents the action of the enzyme. The enzyme was obtained from the lily, Lilium longiflorum.
References:
1.  Ishimizu, T., Sasaki, A., Okutani, S., Maeda, M., Yamagishi, M. and Hase, S. Endo-β-mannosidase, a plant enzyme acting on N-glycan. Purification, molecular cloning, and characterization. J. Biol. Chem. 279 (2004) 38555–38562. [PMID: 15247239]
2.  Sasaki, A., Yamagishi, M., Mega, T., Norioka, S., Natsuka, S. and Hase, S. Partial purification and characterization of a novel endo-β-mannosidase acting on N-linked sugar chains from Lilium longiflorum thumb. J. Biochem. (Tokyo) 125 (1999) 363–367. [PMID: 9990135]
[EC 3.2.1.152 created 2005]
 
 
EC 3.2.1.153     
Accepted name: fructan β-(2,1)-fructosidase
Reaction: Hydrolysis of terminal, non-reducing (2→1)-linked β-D-fructofuranose residues in fructans
Other name(s): β-(2-1)-D-fructan fructohydrolase; β-(2-1)fructan exohydrolase; inulinase; 1-FEH II; 1-fructan exohydrolase; 1-FEH w1; 1-FEH w2; β-(2-1)-linkage-specific fructan-β-fructosidase; β-(2,1)-D-fructan fructohydrolase
Systematic name: β-(2→1)-D-fructan fructohydrolase
Comments: Possesses one of the activities of EC 3.2.1.80, fructan β-fructosidase. While the best substrates are the inulin-type fructans, such as 1-kestose [β-D-fructofuranosyl-(2→1)-β-D-fructofuranosyl α-D-glucopyranoside] and 1,1-nystose [β-D-fructofuranosyl-(2→1)-β-D-fructofuranosyl-(2→1)-β-D-fructofuranosyl α-D-glucopyranoside], some (but not all) levan-type fructans can also be hydrolysed, but more slowly [see EC 3.2.1.154, fructan β-(2,6)-fructosidase]. Sucrose, while being a very poor substrate, can substantially inhibit enzyme activity in some cases.
References:
1.  De Roover, J., Van Laere, A., De Winter, M., Timmermans, J.W. and Van den Ende, W. Purification and properties of a second fructan exohydrolase from the roots of Cichorium intybus. Physiol. Plant. 106 (1999) 28–34.
2.  Van den Ende, W., Clerens, S., Vergauwen, R., Van Riet, L., Van Laere, A., Yoshida, M. and Kawakami, A. Fructan 1-exohydrolases. β-(2,1)-Trimmers during graminan biosynthesis in stems of wheat? Purification, characterization, mass mapping, and cloning of two fructan 1-exohydrolase isoforms. Plant Physiol. 131 (2003) 621–631. [PMID: 12586886]
[EC 3.2.1.153 created 2005]
 
 
EC 3.2.1.154     
Accepted name: fructan β-(2,6)-fructosidase
Reaction: Hydrolysis of terminal, non-reducing (2→6)-linked β-D-fructofuranose residues in fructans
Other name(s): β-(2-6)-fructan exohydrolase; levanase; 6-FEH; β-(2,6)-D-fructan fructohydrolase
Systematic name: (2→6)-β-D-fructan fructohydrolase
Comments: Possesses one of the activities of EC 3.2.1.80, fructan β-fructosidase. While the best substrates are the levan-type fructans such as 6-kestotriose [β-D-fructofuranosyl-(2→6)-β-D-fructofuranosyl α-D-glucopyranoside] and 6,6-kestotetraose [β-D-fructofuranosyl-(2→6)-β-D-fructofuranosyl-(2→6)-β-D-fructofuranosyl α-D-glucopyranoside], some (but not all) inulin-type fructans can also be hydrolysed, but more slowly [cf. EC 3.2.1.153, fructan β-(2,1)-fructosidase]. Sucrose, while being a very poor substrate, can substantially inhibit enzyme activity in some cases.
References:
1.  Marx, S.P., Nösberger, J. and Frehner, M. Hydrolysis of fructan in grasses: A β-(2-6)-linkage specific fructan-β-fructosidase from stubble of Lolium perenne. New Phytol. 135 (1997) 279–290.
2.  Van den Ende, W., De Coninck, B., Clerens, S., Vergauwen, R. and Van Laere, A. Unexpected presence of fructan 6-exohydrolases (6-FEHs) in non-fructan plants: characterization, cloning, mass mapping and functional analysis of a novel 'cell-wall invertase-like' specific 6-FEH from sugar beet (Beta vulgaris L.). Plant J. 36 (2003) 697–710. [PMID: 14617070]
3.  Henson, C.A. and Livingston, D.P. , III. Purification and characterization of an oat fructan exohydrolase that preferentially hydrolyzes β-2,6-fructans. Plant Physiol. 110 (1996) 639–644. [PMID: 8742337]
[EC 3.2.1.154 created 2005]
 
 
EC 3.2.1.155     
Accepted name: xyloglucan-specific exo-β-1,4-glucanase
Reaction: Hydrolysis of (1→4)-D-glucosidic linkages in xyloglucans so as to successively remove oligosaccharides from the chain end.
Other name(s): Cel74A
Systematic name: [(1→6)-α-D-xylo]-(1→4)-β-D-glucan exo-glucohydrolase
Comments: The enzyme removes XXXG heptasaccharides, XXLG/XLXG octasaccharides and XLLG nonasaccharides from the end of tamarind seed xyloglucan polymers in a processive manner. Hydrolysis occurs at the unsubstituted D-glucopyranose residue in the main backbone. It is not known whether the cleavage takes place at the reducing or non-reducing end of the polymer. Very low activity with β-D-glucans. The enzyme from Chrysosporium lucknowense shifts to an endoglucanase mode when acting on linear substrates without bulky substituents on the polymeric backbone such as barley β-glucan.
References:
1.  Grishutin, S.G., Gusakov, A.V., Markov, A.V., Ustinov, B.B., Semenova, M.V. and Sinitsyn, A.P. Specific xyloglucanases as a new class of polysaccharide-degrading enzymes. Biochim. Biophys. Acta 1674 (2004) 268–281. [PMID: 15541296]
[EC 3.2.1.155 created 2005, withdrawn at public-review stage, modified and reinstated 2006, modified 2011]
 
 
EC 3.2.1.156     
Accepted name: oligosaccharide reducing-end xylanase
Reaction: Hydrolysis of (1→4)-β-D-xylose residues from the reducing end of oligosaccharides
Other name(s): Rex; reducing end xylose-releasing exo-oligoxylanase
Systematic name: β-D-xylopyranosyl-(1→4)-β-D-xylopyranose reducing-end xylanase
Comments: The enzyme, originally isolated from the bacterium Bacillus halodurans C-125, releases the xylose unit at the reducing end of oligosaccharides ending with the structure β-D-xylopyranosyl-(1→4)-β-D-xylopyranosyl-(1→4)-β-D-xylopyranose, leaving the new reducing end in the α configuration. It is specific for the β anomers of xylooligosaccharides whose degree of polymerization is equal to or greater than 3. The penultimate residue must be β-D-xylopyranose, but replacing either of the flanking residues with glucose merely slows the rate greatly.
References:
1.  Honda, Y. and Kitaoka, M. A family 8 glycoside hydrolase from Bacillus halodurans C-125 (BH2105) is a reducing end xylose-releasing exo-oligoxylanase. J. Biol. Chem. 279 (2004) 55097–55103. [PMID: 15491996]
2.  Fushinobu, S., Hidaka, M., Honda, Y., Wakagi, T., Shoun, H. and Kitaoka, M. Structural basis for the specificity of the reducing end xylose-releasing exo-oligoxylanase from Bacillus halodurans C-125. J. Biol. Chem. 280 (2005) 17180–17186. [PMID: 15718242]
[EC 3.2.1.156 created 2005]
 
 
EC 3.2.1.157     
Accepted name: ι-carrageenase
Reaction: Endohydrolysis of (1→4)-β-D-linkages between D-galactose 4-sulfate and 3,6-anhydro-D-galactose-2-sulfate in ι-carrageenans
Glossary: In the field of oligosaccharides derived from agarose, carrageenans, etc., in which alternate residues are 3,6-anhydro sugars, the prefix ’neo’ designates an oligosaccharide whose non-reducing end is the anhydro sugar, and the absence of this prefix means that it is not.
For example:
ι-neocarrabiose = 3,6-anhydro-2-O-sulfo-α-D-galactopyranosyl-(1→3)-4-O-sulfo-D-galactose
ι-carrabiose = 4-O-sulfo-β-D-galactopyranosyl-(1→4)-3,6-anhydro-2-O-sulfo-D-galactose
Systematic name: ι-carrageenan 4-β-D-glycanohydrolase (configuration-inverting)
Comments: The main products of hydrolysis are ι-neocarratetraose sulfate and ι-neocarrahexaose sulfate. ι-Neocarraoctaose is the shortest substrate oligomer that can be cleaved. Unlike EC 3.2.1.81, β-agarase and EC 3.2.1.83, κ-carrageenase, this enzyme proceeds with inversion of the anomeric configuration. ι-Carrageenan differs from κ-carrageenan by possessing a sulfo group on O-2 of the 3,6-anhydro-D-galactose residues, in addition to that present in the κ-compound on O-4 of the D-galactose residues.
References:
1.  Barbeyron, T., Michel, G., Potin, P., Henrissat, B. and Kloareg, B. ι-Carrageenases constitute a novel family of glycoside hydrolases, unrelated to that of κ-carrageenases. J. Biol. Chem. 275 (2000) 35499–35505. [PMID: 10934194]
2.  Michel, G., Chantalat, L., Fanchon, E., Henrissat, B., Kloareg, B. and Dideberg, O. The ι-carrageenase of Alteromonas fortis. A β-helix fold-containing enzyme for the degradation of a highly polyanionic polysaccharide. J. Biol. Chem. 276 (2001) 40202–40209. [PMID: 11493601]
3.  Michel, G., Helbert, W., Kahn, R., Dideberg, O. and Kloareg, B. The structural bases of the processive degradation of ι-carrageenan, a main cell wall polysaccharide of red algae. J. Mol. Biol. 334 (2003) 421–433. [PMID: 14623184]
[EC 3.2.1.157 created 2006]
 
 
EC 3.2.1.158     
Accepted name: α-agarase
Reaction: Endohydrolysis of (1→3)-α-L-galactosidic linkages in agarose, yielding agarotetraose as the major product
Glossary: agarose = a polysaccharide
In the field of oligosaccharides derived from agarose, carrageenans, etc., in which alternate residues are 3,6-anhydro sugars, the prefix ’neo’ designates an oligosaccharide whose non-reducing end is the anhydro sugar, and the absence of this prefix means that it is not.
For example:
neoagarobiose = 3,6-anhydro-α-L-galactopyranosyl-(1→3)-D-galactose
agarobiose = β-D-galactopyranosyl-(1→4)-3,6-anhydro-L-galactose
Other name(s): agarase (ambiguous); agaraseA33
Systematic name: agarose 3-glycanohydrolase
Comments: Requires Ca2+. The enzyme from Thalassomonas sp. can use agarose, agarohexaose and neoagarohexaose as substrate. The products of agarohexaose hydrolysis are dimers and tetramers, with agarotetraose being the predominant product, whereas hydrolysis of neoagarohexaose gives rise to two types of trimer. While the enzyme can also hydrolyse the highly sulfated agarose porphyran very efficiently, it cannot hydrolyse the related compounds κ-carrageenan (see EC 3.2.1.83) and ι-carrageenan (see EC 3.2.1.157) [2]. See also EC 3.2.1.81, β-agarase.
References:
1.  Potin, P., Richard, C., Rochas, C. and Kloareg, B. Purification and characterization of the α-agarase from Alteromonas agarlyticus (Cataldi) comb. nov., strain GJ1B. Eur. J. Biochem. 214 (1993) 599–607. [PMID: 8513809]
2.  Ohta, Y., Hatada, Y., Miyazaki, M., Nogi, Y., Ito, S. and Horikoshi, K. Purification and characterization of a novel α-agarase from a Thalassomonas sp. Curr. Microbiol. 50 (2005) 212–216. [PMID: 15902469]
[EC 3.2.1.158 created 2006]
 
 
EC 3.2.1.159     
Accepted name: α-neoagaro-oligosaccharide hydrolase
Reaction: Hydrolysis of the (1→3)-α-L-galactosidic linkages of neoagaro-oligosaccharides that are smaller than a hexamer, yielding 3,6-anhydro-L-galactose and D-galactose
Glossary: In the field of oligosaccharides derived from agarose, carrageenans, etc., in which alternate residues are 3,6-anhydro sugars, the prefix ’neo’ designates an oligosaccharide whose non-reducing end is the anhydro sugar, and the absence of this prefix means that it is not.
For example:
neoagarobiose = 3,6-anhydro-α-L-galactopyranosyl-(1→3)-D-galactose
agarobiose = β-D-galactopyranosyl-(1→4)-3,6-anhydro-L-galactose
Other name(s): α-neoagarooligosaccharide hydrolase; α-NAOS hydrolase
Systematic name: α-neoagaro-oligosaccharide 3-glycohydrolase
Comments: When neoagarohexaose is used as a substrate, the oligosaccharide is cleaved at the non-reducing end to produce 3,6-anhydro-L-galactose and agaropentaose, which is further hydrolysed to agarobiose and agarotriose. With neoagarotetraose as substrate, the products are predominantly agarotriose and 3,6-anhydro-L-galactose. In Vibrio sp. the actions of EC 3.2.1.81, β-agarase and EC 3.2.1.159 can be used to degrade agarose to 3,6-anhydro-L-galactose and D-galactose.
References:
1.  Sugano, Y., Kodama, H., Terada, I., Yamazaki, Y. and Noma, M. Purification and characterization of a novel enzyme, α-neoagarooligosaccharide hydrolase (α-NAOS hydrolase), from a marine bacterium, Vibrio sp. strain JT0107. J. Bacteriol. 176 (1994) 6812–6818. [PMID: 7961439]
[EC 3.2.1.159 created 2006]
 
 


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