The molecule is an amino acid zwitterion obtained via transfer of a proton from the carboxy to the amino group of S-(4-bromophenyl)-L-cysteine; major species at pH 7.3. It is a tautomer of a S-(4-bromophenyl)-L-cysteine.
(2R)-2-azaniumyl-3-(4-bromophenyl)sulfanylpropanoate