The molecule is a derivative of L-serine having a 3-O-D-galactosyl-N-acetyl-beta-D-galactosaminyl moiety attached to the side-chain oxygen. It is an O-glycosyl-L-serine and a non-proteinogenic L-alpha-amino acid. It is a tautomer of an O-(3-O-D-galactosyl-N-acetyl-beta-D-galactosaminyl)-L-serine zwitterion.
(2S)-3-[(2R,3R,4R,5R,6R)-3-acetamido-5-hydroxy-6-(hydroxymethyl)-4-[(3R,4S,5R,6R)-3,4,5-trihydroxy-6-(hydroxymethyl)oxan-2-yl]oxyoxan-2-yl]oxy-2-aminopropanoic acid