URINARY HYDROXYPROLINE PEPTIDES*

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Abstract
Urinary hydroxyproline (hypro) was found predominantly in peptide form, even with large dietary intakes of collagen. These peptides were separated into 5 peaks by ion-exchange chromatography. The peptide elution pattern was similar in a normal subject, patients with rheumatoid arthritis, scleroderma, Marfan''s syndrome, and Hurler''s syndrome and in normal post-partum women. A woman with lupus erythematosus and a male with generalized morphea lacked one peak. The normal person excreted the same peptide fragments on a high gelatin as on hydroxyproline-free diet, but in increased amounts. The following peptides were identified in the urine diketopeperazine of pro-hypro, glu-(hypro, glu), pro-hypro, and gly-pro-hypro. This is the first demonstration of a tripeptide sequence (gly-pro-hypro) in the urine known to occur in the collagen molecule.