Structure of Pig Skin Dermatan Suflate. 1. Distribution of D-Glucuronic Acid Residues

Thee copolymeric structure of pig skin dermatan sulfate was further studied with particular referene to residual glucuronic acid moieties present in the molecule after sequential treatment with testicular hyaluronidase and β-glucuronidase. Subsequent treatment with chondroitinase-AC lead to a further release of glucuronic acid in the form of disaccharides, tetrasaccharidies and higher oligosaccharides/glycopeptides. Since these products contained nonreducing teminal, unsaturated uronic acid residues, it was concluded that some of the residual glucuronic acid moieties were located in ultimate or penultimate reducing terminal chondroitin 4-sulfate repeating periods of fragments obtained after cleavage with testicular hyalyronidase. Additional, single chondroitin 4-sulfate repeating periods were present in the vicinity of the carbohydrate-protein linkage region or elsewhere in the chain. The former periods were regularly obseved 2-3 units apart from the linkage region whereas the latter periods occurred preferentially in sequences like…BBBBABABAAAA…(A and B are chondroitin 4-sulfate and dermatan sulfate repeating periods, respectively).