The molecule is a dipeptide zwitterion obtained by transfer of a proton from the carboxy to the amino terminus of Pro-Hyp. Major species at pH 7.3. It has a role as a human metabolite and a biomarker. It is a tautomer of a Pro-Hyp.
(2S,4R)-4-hydroxy-1-[(2S)-pyrrolidin-1-ium-2-carbonyl]pyrrolidine-2-carboxylate