The molecule is a dizwitterionic form of 2-(3-amino-3-carboxypropyl)-L-histidine arising from transfer of two protons from the carboxy to the amino groups; major species at pH 7.3. It is a tautomer of a 2-(3-amino-3-carboxypropyl)-L-histidine.
2-azaniumyl-4-[5-[(2S)-2-azaniumyl-2-carboxylatoethyl]-1H-imidazol-2-yl]butanoate