Enzyme-assisted synthesis of Asn-linked diantennary oligosaccharides occurring on glycodelin A.

The preparation of a series of sialylated and fucosylated N,N'-diacetyllactosediamine-type diantennary glycopeptides is reported. By sequential enzymatic action of jack bean beta-galactosidase, snail beta 4-N-acetyl-galactosaminyltransferase, bovine colostrum alpha 6-sialyltransferase and human milk alpha 3-fucosyltransferase, a diantennary glycopeptide obtained from asialo fibrinogen was converted at a 5-mumol scale to a series of structures occurring on the glycoprotein glycodelin A, which potentially inhibit human sperm-egg binding.