A new heptasaccharide, lacto-N-fucoheptaose has been isolated from human milk. It contains D(+)-galactose, D(+)-glucose, L(−)-fucose and N−acetyl−D−(+)−glucosamine in a 3 : 1 : 1 : 2 ratio. The glucose residue is at the reducing end of the oligosaccharide. Data obtained by partial acid hydrolysis, permethylation and enzymic hydrolysis establish the structure of lacto-N-fucoheptaose as follows
