ENZYME

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ENZYME entry: EC 4.2.2.20

Accepted Name

Chondroitin-sulfate-ABC endolyase.

Alternative Name(s)

Chondroitin ABC eliminase.

Chondroitin ABC lyase.

Chondroitin sulfate ABC endoeliminase.

Chondroitin sulfate ABC endolyase.

Chondroitin sulfate ABC lyase.

Chondroitinase.

Chondroitinase ABC.

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(beta-1- 3)GalNAc(beta-1-](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(alpha-1-3)GalNAc(beta-1-](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

BRENDA

4.2.2.20

EC2PDB

4.2.2.20

ExplorEnz

4.2.2.20

PRIAM enzyme-specific profiles

4.2.2.20

KEGG Ligand Database for Enzyme Nomenclature

4.2.2.20

IUBMB Enzyme Nomenclature