ID   4.2.2.19
DE   chondroitin B lyase.
AN   ChonB.
AN   chondroitinase B.
CA   Eliminative cleavage of dermatan sulfate containing (1->4)-beta-D-
CA   hexosaminyl and (1->3)-beta-D-glucurosonyl or (1->3)-alpha-L-iduronosyl
CA   linkages to disaccharides containing 4-deoxy-beta-D-gluc-4-enuronosyl
CA   groups to yield a 4,5-unsaturated dermatan-sulfate disaccharide (DeltaUA-
CA   GalNAc-4S).
CC   -!- This is the only lyase that is known to be specific for dermatan
CC       sulfate as substrate.
CC   -!- The minimum substrate length required for catalysis is a
CC       tetrasaccharide.
CC   -!- In general, chondroitin sulfate (CS) and dermatan sulfate (DS) chains
CC       comprise a linkage region, a chain cap and a repeat region.
CC   -!- The repeat region of CS is a repeating disaccharide of glucuronic
CC       acid (GlcA) and N-acetylgalactosamine (GalNAc) [-4)GlcA(beta1-
CC       3)GalNAc(beta1-]n, which may be O-sulfated on the C-4 and/or C-6 of
CC       GalNAc and C-2 of GlcA.
CC   -!- GlcA residues of CS may be epimerized to iduronic acid (IdoA) forming
CC       the repeating disaccharide [-4)IdoA(alpha1-3)GalNAc(beta1-]n of DS.
CC   -!- Both the concentrations and locations of sulfate-ester substituents
CC       vary with glucosaminoglycan source.
DR   Q46079, CSLB_PEDHD ;
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