Accepted name: unsaturated rhamnogalacturonyl hydrolase
Reaction: 2-O-(4-deoxy-β-L-threo-hex-4-enopyranuronosyl)-α-L-rhamnopyranose + H2O = 5-dehydro-4-deoxy-D-glucuronate + L-rhamnopyranose
Glossary: 6-deoxy-2-O-(4-deoxy-β-L-threo-hex-4-enopyranuronosyl)-α-L-mannopyranose = 2-O-(4-deoxy-β-L-threo-hex-4-enopyranuronosyl)-α-L-rhamnopyranose
5-dehydro-4-deoxy-D-glucuronate = (4S,5R)-4,5-dihydroxy-2,6-dioxohexanoate
Other name(s): YteR; YesR
Systematic name: 2-O-(4-deoxy-β-L-threo-hex-4-enopyranuronosyl)-α-L-rhamnopyranose hydrolase
Comments: The enzyme is part of the degradation system for rhamnogalacturonan I in Bacillus subtilis strain 168.
1.  Itoh, T., Ochiai, A., Mikami, B., Hashimoto, W. and Murata, K. A novel glycoside hydrolase family 105: the structure of family 105 unsaturated rhamnogalacturonyl hydrolase complexed with a disaccharide in comparison with family 88 enzyme complexed with the disaccharide. J. Mol. Biol. 360 (2006) 573–585. [PMID: 16781735]
2.  Zhang, R., Minh, T., Lezondra, L., Korolev, S., Moy, S.F., Collart, F. and Joachimiak, A. 1.6 Å crystal structure of YteR protein from Bacillus subtilis, a predicted lyase. Proteins 60 (2005) 561–565. [PMID: 15906318]
3.  Itoh, T., Ochiai, A., Mikami, B., Hashimoto, W. and Murata, K. Structure of unsaturated rhamnogalacturonyl hydrolase complexed with substrate. Biochem. Biophys. Res. Commun. 347 (2006) 1021–1029. [PMID: 16870154]
[EC created 2011, modified 2012]
Accepted name: gellan tetrasaccharide unsaturated glucuronosyl hydrolase
Reaction: β-D-4-deoxy-Δ4-GlcAp-(1→4)-β-D-Glcp-(1→4)-α-L-Rhap-(1→3)-D-Glcp + H2O = 5-dehydro-4-deoxy-D-glucuronate + β-D-Glcp-(1→4)-α-L-Rhap-(1→3)-D-Glcp
Glossary: 5-dehydro-4-deoxy-D-glucuronate = (4S,5R)-4,5-dihydroxy-2,6-dioxohexanoate
β-D-4-deoxy-Δ4-GlcAp-(1→3)-D-GalNAc = 3-(4-deoxy-β-D-gluc-4-enuronosyl)-N-acetyl-D-galactosamine = 3-(4-deoxy-α-L-threo-hex-4-enopyranosyluronic acid)-2-acetamido-2-deoxy-D-galactose
Other name(s): UGL (ambiguous); unsaturated glucuronyl hydrolase (ambiguous); gellan tetrasaccharide unsaturated glucuronyl hydrolase
Systematic name: β-D-4-deoxy-Δ4-GlcAp-(1→4)-β-D-Glcp-(1→4)-α-L-Rhap-(1→3)-D-Glcp β-D-4-deoxy-Δ4-GlcAp hydrolase
Comments: The enzyme releases 4-deoxy-4(5)-unsaturated D-glucuronic acid from oligosaccharides produced by polysaccharide lyases, e.g. the tetrasaccharide β-D-4-deoxy-Δ4-GlcAp-(1→4)-β-D-Glcp-(1→4)-α-L-Rhap-(1→3)-D-Glcp produced by EC, gellan lyase. The enzyme can also hydrolyse unsaturated chondroitin and hyaluronate disaccharides (β-D-4-deoxy-Δ4-GlcAp-(1→3)-D-GalNAc, β-D-4-deoxy-Δ4-GlcAp-(1→3)-D-GalNAc6S, β-D-4-deoxy-Δ4-GlcAp2S-(1→3)-D-GalNAc, β-D-4-deoxy-Δ4-GlcAp-(1→3)-D-GlcNAc), preferring the unsulfated disaccharides to the sulfated disaccharides.
1.  Itoh, T., Akao, S., Hashimoto, W., Mikami, B. and Murata, K. Crystal structure of unsaturated glucuronyl hydrolase, responsible for the degradation of glycosaminoglycan, from Bacillus sp. GL1 at 1.8 Å resolution. J. Biol. Chem. 279 (2004) 31804–31812. [PMID: 15148314]
2.  Hashimoto, W., Kobayashi, E., Nankai, H., Sato, N., Miya, T., Kawai, S. and Murata, K. Unsaturated glucuronyl hydrolase of Bacillus sp. GL1: novel enzyme prerequisite for metabolism of unsaturated oligosaccharides produced by polysaccharide lyases. Arch. Biochem. Biophys. 368 (1999) 367–374. [PMID: 10441389]
3.  Itoh, T., Hashimoto, W., Mikami, B. and Murata, K. Substrate recognition by unsaturated glucuronyl hydrolase from Bacillus sp. GL1. Biochem. Biophys. Res. Commun. 344 (2006) 253–262. [PMID: 16630576]
[EC created 2011, modified 2016]
Accepted name: unsaturated chondroitin disaccharide hydrolase
Reaction: β-D-4-deoxy-Δ4-GlcAp-(1→3)-β-D-GalNAc6S + H2O = 5-dehydro-4-deoxy-D-glucuronate + N-acetyl-β-D-galactosamine-6-O-sulfate
Glossary: 5-dehydro-4-deoxy-D-glucuronate = (4S,5R)-4,5-dihydroxy-2,6-dioxohexanoate
Other name(s): UGL (ambiguous); unsaturated glucuronyl hydrolase (ambiguous)
Systematic name: β-D-4-deoxy-Δ4-GlcAp-(1→3)-β-D-GalNAc6S hydrolase
Comments: The enzyme releases 4-deoxy-4,5-didehydro D-glucuronic acid or 4-deoxy-4,5-didehydro L-iduronic acid from chondroitin disaccharides, hyaluronan disaccharides and heparin disaccharides and cleaves both glycosidic (1→3) and (1→4) bonds. It prefers the sulfated disaccharides to the unsulfated disaccharides.
1.  Maruyama, Y., Nakamichi, Y., Itoh, T., Mikami, B., Hashimoto, W. and Murata, K. Substrate specificity of streptococcal unsaturated glucuronyl hydrolases for sulfated glycosaminoglycan. J. Biol. Chem. 284 (2009) 18059–18069. [PMID: 19416976]
2.  Nakamichi, Y., Maruyama, Y., Mikami, B., Hashimoto, W. and Murata, K. Structural determinants in streptococcal unsaturated glucuronyl hydrolase for recognition of glycosaminoglycan sulfate groups. J. Biol. Chem. 286 (2011) 6262–6271. [PMID: 21147778]
[EC created 2011]
Accepted name: oligogalacturonide lyase
Reaction: 4-(4-deoxy-α-D-galact-4-enuronosyl)-D-galacturonate = 2 5-dehydro-4-deoxy-D-glucuronate
Other name(s): oligogalacturonate lyase; unsaturated oligogalacturonate transeliminase; OGTE
Systematic name: oligogalacturonide lyase
Comments: Also catalyses eliminative removal of unsaturated terminal residues from oligosaccharides of D-galacturonate.
1.  Moran, F., Nasuno, S. and Starr, M.P. Oligogalacturonide trans-eliminase of Erwinia carotovora. Arch. Biochem. Biophys. 125 (1968) 734–741. [PMID: 5671040]
[EC created 1972, modified 2010]
Accepted name: 5-dehydro-4-deoxy-D-glucuronate isomerase
Reaction: 5-dehydro-4-deoxy-D-glucuronate = 3-deoxy-D-glycero-2,5-hexodiulosonate
Glossary: 5-dehydro-4-deoxy-D-glucuronate = (4S,5R)-4,5-dihydroxy-2,6-dioxohexanoate
3-deoxy-D-glycero-2,5-hexodiulosonate = (4S)-4,6-dihydroxy-2,5-dioxohexanoate
Other name(s): 4-deoxy-L-threo-5-hexulose uronate isomerase; 4-deoxy-L-threo-5-hexosulose-uronate ketol-isomerase; kduI (gene name)
Systematic name: 5-dehydro-4-deoxy-D-glucuronate aldose-ketose-isomerase
Comments: The enzyme is involved in the degradation of polygalacturonate, a later stage in the degradation of pectin by many microorganisms.
1.  Preiss, J. 4-Deoxy-L-threo-5-hexosulose uronic acid isomerase. Methods Enzymol. 9 (1966) 602–604.
2.  Condemine, G. and Robert-Baudouy, J. Analysis of an Erwinia chrysanthemi gene cluster involved in pectin degradation. Mol. Microbiol. 5 (1991) 2191–2202. [PMID: 1766386]
3.  Dunten, P., Jaffe, H. and Aksamit, R.R. Crystallization of 5-keto-4-deoxyuronate isomerase from Escherichia coli. Acta Crystallogr. D Biol. Crystallogr. 54 (1998) 678–680. [PMID: 9761873]
4.  Crowther, R.L. and Georgiadis, M.M. The crystal structure of 5-keto-4-deoxyuronate isomerase from Escherichia coli. Proteins 61 (2005) 680–684. [PMID: 16152643]
[EC created 1972, modified 2012]