Micro-Heterogeneity in the Biosynthesis of Collagen Detailed analyses of the structure of the polypeptide chains of collagen has revealed a micro-heterogeneity of the amino acid sequences. Sequencing of the first 50 amino acid residues from the NH2-terminal end of the 1 chain of rat skin and tendon collagen indicated that although there were several triplets of the structure -Gly-X-Hypro-, an appreciable fraction of the amino acid in the third position of such triplets was Pro rather than Hypro.109,110 A similar situation has been found for Hypro in most109,110,139,140 but not all141,142 of the triplets that have been. 1972, Massachusetts Medical Society. All rights reserved.
