ENZYME entry: 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 (Delta-UA-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(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.
|
| Cross-references |
|---|
| BRENDA | 4.2.2.19 |
| EC2PDB | 4.2.2.19 |
| ExplorEnz | 4.2.2.19 |
| PRIAM enzyme-specific profiles | 4.2.2.19 |
| KEGG Ligand Database for Enzyme Nomenclature | 4.2.2.19 |
| IUBMB Enzyme Nomenclature | 4.2.2.19 |
| IntEnz | 4.2.2.19 |
| MEDLINE | Find literature relating to 4.2.2.19 |
| MetaCyc | 4.2.2.19 |
| Rhea expert-curated reactions | 4.2.2.19 |
| UniProtKB/Swiss-Prot |
|
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