Characterization and Hydroxylysine-linked of Several Collagen8

The hydroxylysine-containing glycopeptides from collagenase-Pronase digests of bovine tendon collagen were found to have glucose and galactose as their monosaccharide components. The ratio of galactose to glucose in these glycopeptides was greater than unity and after alkaline hydrolysis both glucosylgalactosylhydroxylysine and galactosylhydroxylysine were found. In order to determine the content of glucosylgalactosylhydroxylysine, galactosylhydroxylysine, and unsubstituted hydroxylysine present in tendon collagen as well as in several other collagens, analyses for these components were performed on the amino acid analyzer after alkaline hydrolysis. The other collagens studied were obtained from rat skin, rat tail tendon, carp swim bladder, rabbit sclera, and corneas from rabbits and calves. From most of these sources both the citrate-soluble and citrate-insoluble collagens were studied. In all of the proteins studied both glucosylgalactosylhydroxylysine and galactosylhydroxylysine were found, with the galactosylhydroxylysine making up from 46% of the total hydroxylysine-linked carbohydrate units in calf skin citratesoluble collagen to 11% in carp swim bladder citrate-insoluble collagen. The citrate-insoluble collagens tended to contain a greater percentage of glucosylgalactosylhydroxylysine units than the citrate-soluble collagens from the same source. The percentage of the total hydroxylysine residues substituted by the glycosidic linkages of these units varied from 5% in rat tail tendon citrate-soluble collagen (0.4 carbohydrate unit/1000 amino acid residues) to 56% in the rabbit cornea citrate-insoluble collagen (5.8 carbohydrate units/ 1000 amino acid residues). All these collagens were shown to contain markedly fewer hydroxylysine-linked carbohydrate units than basement membranes, suggesting that higher levels of hydroxylysinelinked carbohydrate are reflected in lower degrees of mor-