Evidence for the Linkage of a Disaccharide to Hydroxylysine in Tropocollagen

Abstract Soluble collagen from guinea pig skin has been subjected to sequential digestion with purified collagenase and trypsin. The small quantity of hexose present in the collagen can be detected in the digest largely as relatively basic glycopeptides. One of these glycopeptides has been obtained in pure form and accounts for at least 30% of the hexose of the original collagen. This glycopeptide has been shown to consist of a disaccharide of glucose and galactose linked O-glycosidically to the hydroxyl group of a hydroxylysine residue in a special peptide region of the collagen molecule. The amino acid composition and probable sequence in this region was shown to be -Gly-Met-Hyl(Glc, Gal)-Gly-His-Arg- A possible role for this structure in the formation of cross-links during collagen maturation is described.