The molecule is a tripeptide composed of L-proline, L-arginine and L-proline joined in sequence by peptide linkages. It derives from a L-proline and a L-arginine.
(2S)-1-[(2S)-5-(diaminomethylideneamino)-2-[[(2S)-pyrrolidine-2-carbonyl]amino]pentanoyl]pyrrolidine-2-carboxylic acid