The molecule is an amino acid zwitterion arising from transfer of a proton from the carboxy to the amino group of 5-hydroxy-L-tryptophan; major species at pH 7.3. It is a tautomer of a 5-hydroxy-L-tryptophan.
(2S)-2-azaniumyl-3-(5-hydroxy-1H-indol-3-yl)propanoate