Subunit structure of isomeric chondroitin sulfates from normal human urine

In addition to the well-known 4-sulfated, 6-sulfated, and non-sulfated disaccharide subunits, chondroitinase AC-digests of urinary glycosaminoglycans from normal individuals contained two kinds of oversulfated disaccharides as minor structural subunits. The results of the digestion with chondrosulfatases indicated that one of these oversulfated disaccharides might be Δ⁴-glucuronido - acetylgalactosamine - 4,6-disulfate, while the other seemed to be Δ⁴-sulfoglucuronido - acetylgalactosamine-6-sulfate. Chondroitinase ABC-digests of urinary dermatan sulfate also contained an oversulfated disaccharide as a minor structural subunit which appeared to be a derivative of 4-sulfated disaccharide bearing an extrasulfate residue on the uronic acid moiety, Δ⁴-sulfoglucuronido-acetylgalactosamine-4-sulfate.One hybrid oligosaccharide was identified in the chondroitinase AC-digests of urinary glycosaminoglycans. It was degraded by chondroitinase ABC to yield 4-sulfated and 6-sulfated disaccharides at a molar ratio of 3 to 1. These results suggested that hybrid structure might be present in urinary dermatan sulfate chains.