Age-dependent changes of chondroitin sulfate isomers in normal human urine

Abstract 1. 1. Urinary chondroitin sulfate isomers, which are the major constituents of acidic glycosaminoglycans in normal human urine at various ages, were determined at the disaccharide subunits by digestion with chondroitinase-ABC. 2. 2. In normal human urine, chondroitin 4-sulfate and chondroitin 6-sulfate followed by their undersulfated isomers were found to be the major components of urinary acidic glycosaminoglycans. 3. 3. Chondroitin 4-sulfate was the greatest urinary acidic glycosaminoglycans in childhood, followed by chondroitin 6-sulfate. An increase of desulfation of the chondroitin sulfates with the advance of age was correlated to a decrease of chondroitin 4-sulfate. 4. 4. The proportion of chondroitin 4-sulfate to chondroitin 6-sulfate decreased with the advance of age in urinary acidic glycosaminoglycans prepared from normal adults after adolescence. 5. 5. Electrophoretic evidence with above findings indicates possible hybrid structures of the 4-sulfated and 6-sulfated disaccharide subunits which locate on the same disaccharide chain to form chondroitin sulfate isomers in the macromolecular state.