Glycylhydroxyprolyl Sequences in Earthworm Cuticle Collagen: Glycylhydroxyprolylserine

A second tripeptide representing a glycylhydroxyprolyl sequence, glycylhydroxyprolylserine, has been isolated from purified earthworm cuticle collagen following digestion of the denatured collagen by clostridial collagenase. This tripeptide was estimated to represent 4 to 5% of the total hydroxyproline in the peptide mixture released by collagenase action. The isomeric tripeptide, glycylserylhydroxyproline, was not detected but could have been present at a maximum concentration representing another 4% of the total peptide hydroxyproline. Data are presented on the susceptibility of native and denatured earthworm cuticle collagen to clostridial collagenase and on the amino acid composition and chromato-graphic behavior of a number of peptide fractions obtained from collagenase digests of earthworm cuticle collagen.