Microheterogeneity of chondroitin sulfates from various cartilages

Chondroitin sulfate fractions were isolated from different animal cartilages, including whale, cattle, sheep, ray and shark, by Dowex 1 chromatography followed by ethanol fractionation. Although each preparation showed a single spot when electrophoresed on cellulose acetate, both 4- and 6-sulfated disaccharides were present in chondroitinase digests of each. In particular, the main fraction of bovine tracheal chondroitin sulfate (SO4/Ga1N = 1) gave both the disaccharides in nearly equal amounts, and its IR spectrum showed absorption bands at 820 and 850 cm-1. This fraction yielded three types of tetrasaccharides after digestion with testicular hyaluronidase. Structural studies on these tetrasaccharides, using P. vulgaris chondro-4-sulfatase followed by chondroitinase, showed that one of them is a hybrid consisting of the 4- and 6-sulfated residues. In the light of these facts, a nomenclature for chondroitin sulfates is discussed.