Chemical nature of human urinary glycosaminoglycans.

To elucidate precise chemical nature of urinary glycosaminoglycans (GAG), GAG in the seven major acidic subfractions in a previous paper (Endo et al. 1980a) were analyzed for the chemical compositions and studied on the linkage between carbohydrate and peptide. All the subfractions examined contained galactosamine, hexuronic acid as the major constituent sugars, and xylose, galactose, L-fucose as the minor ones. Some of the subfractions contained additional glucosamine. Sulfate was also found in all the subfractions as their major constituent. The contents of total amino acids ranged from 1.20 to 17.9%. Serine, threonine, aspartic acid, glutamic acid, glycine, alanine and leucine were found as major amino acids. Pronase digestion did not significantly change their molecular size. The presence of O-xylosyl-serine linkage between carbohydrate chains and peptide moieties ws verified byan alkali treatment. Nevertheless, the presence of small portions of galactose and xylose residues at the reducing ends of the carbohydrate chains suggested a possibility of exertion of endo-beta-galactosidase and endo-beta-xylosidase activities for the linkage regions.