:Unsaturated chondroitin disaccharide hydrolase

{{Short description|Class of enzymes}}

{{Infobox enzyme

| Name = Unsaturated chondroitin disaccharide hydrolase

| EC_number = 3.2.1.180

| CAS_number =

| GO_code =

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Unsaturated chondroitin disaccharide hydrolase ({{EC number|3.2.1.180}}, UGL, unsaturated glucuronyl hydrolase) is an enzyme with systematic name beta-D-4-deoxy-Delta4-GlcAp-(1->3)-beta-D-GalNAc6S hydrolase.{{cite journal | vauthors = Maruyama Y, Nakamichi Y, Itoh T, Mikami B, Hashimoto W, Murata K | title = Substrate specificity of streptococcal unsaturated glucuronyl hydrolases for sulfated glycosaminoglycan | journal = J. Biol. Chem. | volume = 284 | issue = 27 | pages = 18059–69 | date = July 2009 | pmid = 19416976 | pmc = 2709336 | doi = 10.1074/jbc.M109.005660| doi-access = free }}{{cite journal | vauthors = Nakamichi Y, Maruyama Y, Mikami B, Hashimoto W, Murata K | title = Structural determinants in streptococcal unsaturated glucuronyl hydrolase for recognition of glycosaminoglycan sulfate groups | journal = J. Biol. Chem. | volume = 286 | issue = 8 | pages = 6262–71 | date = February 2011 | pmid = 21147778 | pmc = 3057837 | doi = 10.1074/jbc.M110.182618 | doi-access = free }} This enzyme catalyses the following chemical reaction

: beta-D-4-deoxy-Delta4-GlcAp-(1->3)-beta-D-GalNAc6S + H₂O $\backslash rightleftharpoons$ 5-dehydro-4-deoxy-D-glucuronate + N-acetyl-beta-D-galactosamine-6-O-sulfate

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.