EC 4.2.2.19     
Accepted name: chondroitin B lyase
Reaction: Eliminative cleavage of dermatan sulfate containing (1→4)-β-D-hexosaminyl and (1→3)-β-D-glucurosonyl or (1→3)-α-L-iduronosyl linkages to disaccharides containing 4-deoxy-β-D-gluc-4-enuronosyl groups to yield a 4,5-unsaturated dermatan-sulfate disaccharide (ΔUA-GalNAc-4S).
Glossary: chondroitin sulfate B = dermatan sulfate
For the nomenclature of glycoproteins, glycopeptides and peptidoglycans, click here
Other name(s): chondroitinase B; ChonB; ChnB
Systematic name: chondroitin B lyase
Comments: 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 [2]. 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(β1-3)GalNAc(β1-]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(α1-3)GalNAc(β1-]n of DS. Both the concentrations and locations of sulfate-ester substituents vary with glucosaminoglycan source [5].
References:
1.  Gu, K., Linhardt, R.J., Laliberte, M., Gu, K. and Zimmermann, J. Purification, characterization and specificity of chondroitin lyases and glycuronidase from Flavobacterium heparinum. Biochem. J. 312 (1995) 569–577. [PMID: 8526872]
2.  Pojasek, K., Raman, R., Kiley, P., Venkataraman, G. and Sasisekharan, R. Biochemical characterization of the chondroitinase B active site. J. Biol. Chem. 277 (2000) 31179–31186. [PMID: 12063249]
3.  Pojasek, K., Shriver, Z., Kiley, P., Venkataraman, G. and Sasisekharan, R. Recombinant expression, purification, and kinetic characterization of chondroitinase AC and chondroitinase B from Flavobacterium heparinum. Biochem. Biophys. Res. Commun. 286 (2001) 343–351. [PMID: 11500043]
4.  Suzuki, K., Terasaki, Y. and Uyeda, M. Inhibition of hyaluronidases and chondroitinases by fatty acids. J. Enzyme 17 (2002) 183–186. [PMID: 12443044]
5.  Ototani, N. and Yosizawa, Z. Purification of chondroitinase B and chondroitinase C using glycosaminoglycan-bound AH-Sepharose 4B. Carbohydr. Res. 70 (1979) 295–306. [PMID: 427837]
6.  Tkalec, A.L., Fink, D., Blain, F., Zhang-Sun, G., Laliberte, M., Bennett, D.C., Gu, K., Zimmermann, J.J. and Su, H. Isolation and expression in Escherichia coli of cslA and cslB, genes coding for the chondroitin sulfate-degrading enzymes chondroitinase AC and chondroitinase B, respectively, from Flavobacterium heparinum. Appl. Environ. Microbiol. 66 (2000) 29–35. [PMID: 10618199]
7.  Michel, G., Pojasek, K., Li, Y., Sulea, T., Linhardt, R.J., Raman, R., Prabhakar, V., Sasisekharan, R. and Cygler, M. The structure of chondroitin B lyase complexed with glycosaminoglycan oligosaccharides unravels a calcium-dependent catalytic machinery. J. Biol. Chem. 279 (2004) 32882–32896. [PMID: 15155751]
8.  Li, Y., Matte, A., Su, H. and Cygler, M. Crystallization and preliminary X-ray analysis of chondroitinase B from Flavobacterium heparinum. Acta Crystallogr. D Biol. Crystallogr. 55 (1999) 1055–1057. [PMID: 10216304]
9.  Huang, W., Matte, A., Li, Y., Kim, Y.S., Linhardt, R.J., Su, H. and Cygler, M. Crystal structure of chondroitinase B from Flavobacterium heparinum and its complex with a disaccharide product at 1.7 Å resolution. J. Mol. Biol. 294 (1999) 1257–1269. [PMID: 10600383]
10.  Huckerby, T.N., Nieduszynski, I.A., Giannopoulos, M., Weeks, S.D., Sadler, I.H. and Lauder, R.M. Characterization of oligosaccharides from the chondroitin/dermatan sulfates. 1H-NMR and 13C-NMR studies of reduced trisaccharides and hexasaccharides. FEBS J. 272 (2005) 6276–6286. [PMID: 16336265]
[EC 4.2.2.19 created 2005]