ENZYME

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ENZYME entry: EC 4.2.2.21

Accepted Name

Chondroitin-sulfate-ABC exolyase.

Alternative Name(s)

Chondroitin ABC eliminase.

Chondroitin ABC lyase.

Chondroitin sulfate ABC exoeliminase.

Chondroitin sulfate ABC exolyase.

Chondroitin sulfate ABC lyase.

Chondroitinase.

Chondroitinase ABC.

ChS ABC lyase.

ChS ABC lyase II.

Reaction catalysed

Exolytic removal of Delta(4)-unsaturated disaccharide residues from the non-reducing ends of both polymeric chondroitin/dermatan sulfates and their oligosaccharide fragments

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.
The related enzyme EC 4.2.2.20 has the same substrate specificity but produces a mixture of oligosaccharides of different sizes that are ultimately degraded to tetra- and disaccharides.
Both enzymes act by the removal of a relatively acidic C-5 proton of the uronic acid followed by the elimination of a 4-linked hexosamine, resulting in the formation of an unsaturated C4-C5 bond on the hexuronic acid moiety of the products.
Formerly EC 4.2.2.4 and EC 4.2.99.6.

Cross-references

BRENDA

4.2.2.21

EC2PDB

4.2.2.21

ExplorEnz

4.2.2.21

PRIAM enzyme-specific profiles

4.2.2.21

KEGG Ligand Database for Enzyme Nomenclature

4.2.2.21

IUBMB Enzyme Nomenclature