The molecule is a disacccharide consisting of beta-D-galactopyranose and alpha-D-glucopyranose linked in sequence by a (1->3) glycosidic bond. It derives from a beta-D-galactose and an alpha-D-glucose.
(2S,3R,4S,5R,6R)-6-(hydroxymethyl)-4-[(2S,3R,4S,5R,6R)-3,4,5-trihydroxy-6-(hydroxymethyl)oxan-2-yl]oxyoxane-2,3,5-triol