The molecule is a trisaccharide consisting of two beta-D-galactopyranose residues and a D-glucopyranose residue joined in sequence by (1->4) and (1->3) glycosidic bonds. It derives from a beta-D-galactopyranosyl-(1->4)-beta-D-galactopyranose and a D-glucopyranose.
(3R,4S,5R,6R)-4-[(2S,3R,4R,5R,6R)-3,4-dihydroxy-6-(hydroxymethyl)-5-[(2S,3R,4S,5R,6R)-3,4,5-trihydroxy-6-(hydroxymethyl)oxan-2-yl]oxyoxan-2-yl]oxy-6-(hydroxymethyl)oxane-2,3,5-triol