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Information on EC 4.2.2.20 - chondroitin-sulfate-ABC endolyase

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EC Tree
     4 Lyases
         4.2 Carbon-oxygen lyases
             4.2.2 Acting on polysaccharides
                4.2.2.20 chondroitin-sulfate-ABC endolyase
IUBMB Comments
This enzyme 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, chondroitin-sulfate-ABC exolyase, 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 .
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Word Map
The expected taxonomic range for this enzyme is: Eukaryota, Bacteria
Synonyms
Ch'ase, Ch'ase ABC, chABC, chondroitinase ABC, chondroitinase ABC I, chondroitinase AC, ChS ABC lyase I, EC 4.2.2.4, more
REACTION
REACTION DIAGRAM
COMMENTARY hide
ORGANISM
UNIPROT
LITERATURE
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 Delta4-unsaturated oligosaccharides of different sizes that are ultimately degraded to Delta4-unsaturated tetra- and disaccharides
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