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ENZYME

ENZYME entry: EC 4.2.2.20

PURL: https://purl.expasy.org/enzyme/EC/4.2.2.20
Accepted Name
chondroitin-sulfate-ABC endolyase
Alternative Name(s)
chondroitin ABC eliminase
chondroitin ABC lyase
chondroitinase
chondroitinase ABC
chondroitin sulfate ABC endoeliminase
chondroitin sulfate ABC endolyase
chondroitin sulfate ABC lyase
ChS ABC lyase
ChS ABC lyase I
Reaction catalysed
Endolytic cleavage of (1->4)-beta-galactosaminic bonds between N-acetylgalactosamine and either D-glucuronic acid or L-iduronic acid to produce a mixture of Delta(4)-unsaturated oligosaccharides of different sizes that are ultimately degraded to Delta(4)-unsaturated tetra- and disaccharides
Comment(s)
  • Degrades a variety of glycosaminoglycans of the chondroitin-sulfate- and dermatan-sulfate type.
  • Chondroitin sulfate, chondroitin-sulfate proteoglycan and dermatan sulfate are the best substrates but the enzyme can also act on hyaluronan at a much lower rate.
  • Keratan sulfate, heparan sulfate and heparin are not substrates.
  • 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.
  • The related enzyme EC 4.2.2.21 has the same substrate specificity but removes disaccharide residues from the non-reducing ends of both polymeric chondroitin sulfates and their oligosaccharide fragments produced by EC 4.2.2.20.
  • Formerly EC 4.2.2.4 and EC 4.2.99.6.
Cross-references
BRENDA4.2.2.20
EC2PDB4.2.2.20
ExplorEnz4.2.2.20
KEGG Ligand Database for Enzyme Nomenclature4.2.2.20
IUBMB Enzyme Nomenclature4.2.2.20
MEDLINEFind literature relating to 4.2.2.20
MetaCyc4.2.2.20
Rhea expert-curated reactions4.2.2.20
UniProtKB/Swiss-Prot
P59807, CABC1_PROVUT2KMH5, PLH29_FORAG

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