Chondroitin sulfates are widely distributed in human and animal tissues and are the main constituents of cartilage'. The two major isomeric chondroitin sulfates, A (ChS-A) and C (ChS-C) are isolated as glycosaminoglycan from the proteoglycans present in tissues'. Structural investigations have shown that ChS-A and ChS-C both are co-polymers of D-glucuronic acid and sulfated 2-acetamido-2-deoxy-pgalactose. ChS-A primarily contains 4-sulfated 2-acetamido-2-deoxy-D-galactose residues, while ChS-C primarily contains 6-sulfated 2-acetamido-2-deoxy-o-galactose residues. Dermatan sulfate (DS) is a related glycosaminoglycan, often called chondroitin sulfate B (ChS-B), composed of 4-sulfated 2-acetamido-2-deoxy-ogalactose residues. DS differs from ChS-A and ChS-C since its primary uranic acid residue is L-iduronic acid instead of p-glucuronic acid. Despite these structural differences ChS-A, ChS-C, and DS also contain the minor uranic acid C-S epimer (L-iduronic acid in ChS-A and ChS-C and p-glucuronic acid in DS) in their structures.
The chondroitin lyases depolymerize the ChS-A, ChS-C, and DS by an elimination mechanism into oligosaccharides containing a A,,,-unsaturated uranic acid residue at the nonreducing end3T4 (Fig. 1). This residue exhibits an absorbance maximum at 232 nm permitting the detection of the oligosaccharide products of the chondroitin lyases using UV spectroscopy. The chondroitin lyases include ABC, AC, B, and C lyases and are microbial enzymes produced by the using ChS or DS as an inducer3*4. Two different chondroitin AC lyases are commercially available. Chondroitin AC lyase I (AC Flavo) is prepared from Fluvobacterium heparinum and chondroitin AC lyase II (AC Arthro) is prepared from Arthrobacter aurescens. F. heparinum also contains a chondroitin B lyase while A. aurescens does not3. Other bacteria also reportedly produce chondroitin AC lyase including: * Corresponding author.