The Chondroitin 4-Sulfate-Protein Linkage

The nature of the carbohydrate-protein linkage in the chondroitin 4-sulfate-protein complex of bovine nasal septum has been investigated. Two carbohydrate-serine compounds, xylosylserine and galactosylxylosylserine, were isolated from the complex by enzymatic degradation followed by mild acid hydrolysis. Their structures were established as O-β-d-xylopyranosyl-l-serine and 4-O-β-d-galactopyranosyl-O-β-d-xylopyranosyl-l-serine. These findings show that the carbohydrate-protein linkage in the chondroitin 4-sulfate-protein complex is a glycosidic linkage between xylose and the hydroxyl group of serine.