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ENZYME

ENZYME entry: EC 4.2.2.19

PURL: https://purl.expasy.org/enzyme/EC/4.2.2.19
Accepted Name
chondroitin B lyase
Alternative Name(s)
ChonB
chondroitinase B
Reaction catalysed
Eliminative cleavage of dermatan sulfate containing (1->4)-beta-D-hexosaminyl and (1->3)-beta-D-glucurosonyl or (1->3)-alpha-L-iduronosyl linkages to disaccharides containing 4-deoxy-beta-D-gluc-4-enuronosyl groups to yield a 4,5-unsaturated dermatan-sulfate disaccharide (DeltaUA-GalNAc-4S)
Comment(s)
  • This is the only lyase that is known to be specific for dermatan sulfate as substrate.
  • The minimum substrate length required for catalysis is a tetrasaccharide.
  • In general, chondroitin sulfate (CS) and dermatan sulfate (DS) chains comprise a linkage region, a chain cap and a repeat region.
  • The repeat region of CS is a repeating disaccharide of glucuronic acid (GlcA) and N-acetylgalactosamine (GalNAc) [-4)GlcA(beta1- 3)GalNAc(beta1-]n, which may be O-sulfated on the C-4 and/or C-6 of GalNAc and C-2 of GlcA.
  • GlcA residues of CS may be epimerized to iduronic acid (IdoA) forming the repeating disaccharide [-4)IdoA(alpha1-3)GalNAc(beta1-]n of DS.
  • Both the concentrations and locations of sulfate-ester substituents vary with glucosaminoglycan source.
Cross-references
BRENDA4.2.2.19
EC2PDB4.2.2.19
ExplorEnz4.2.2.19
KEGG Ligand Database for Enzyme Nomenclature4.2.2.19
IUBMB Enzyme Nomenclature4.2.2.19
MEDLINEFind literature relating to 4.2.2.19
MetaCyc4.2.2.19
Rhea expert-curated reactions4.2.2.19
UniProtKB/Swiss-Prot
Q46079, CSLB_PEDHD

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