The molecule is an L-tyrosine in which one of the beta-hydrogens in L-tyrosine is replaced by a L-histidino group joined via the N(pros)-position. It is a L-tyrosine derivative and a non-proteinogenic L-alpha-amino acid.
(2S,3R)-2-amino-3-[5-[(2S)-2-amino-2-carboxyethyl]imidazol-1-yl]-3-(4-hydroxyphenyl)propanoic acid