Copolymers of chondroitin 4-sulfate and chondroitin 6-sulfate in chick embryo epiphyses and other cartilage.

Tetrasaccharides were prepared from chondroitin sulfate by means of a limited degradation with chondroitinase ABC. Tetrasaccharides containing one sulfate per disaccharide unit were isolated and were found to be of three types: a tetrasaccharide with two 6-sulfated disaccharide units, a tetrasaccharide with two 4-sulfated disaccharide units, and a tetrasaccharide with one 4-sulfated disaccharide unit and one 6-sulfated disaccharide unit. Samples of each of these three types of tetrasaccharides were obtained from chick embryo epiphyseal cartilage and from a mixture of bovine tracheal cartilage and shark cartilage. The presence of both a 4-sulfated disaccharide unit and a 6-sulfated disaccharide unit in the same tetrasaccharide molecule indicates the existence of mixed 4 and 6 sulfation on the same chondroitin sulfate chain.