The molecule is a dipeptide zwitterion obtained by transfer of a proton from the carboxy to the amino terminus of Phe-His. Major species at pH 7.3. It is a tautomer of a member of Phe-His.
(2S)-2-[[(2S)-2-azaniumyl-3-phenylpropanoyl]amino]-3-(1H-imidazol-5-yl)propanoate