Efficient enzymatic synthesis of the sialyl‐LewisX tetrasaccharide

Abstract
Sialyl‐Lewisx (NeuAcα2→3Galβ1→4[Fucαl→3]GlcNAc] has been identified as a ligand for E‐selectin, P‐selectin and recently also for L‐selectin. We have synthesized the sialyl‐Lewisx tetrasaccharide by total enzymatic synthesis from N‐acetyllactosamine using a placental α2→3‐sialyltransferase specific for type‐2 chain acceptors, followed by a cloned human α1→3‐fucosyltransferase (FucTV, the ‘plasma‐type’ enzyme). This procedure resulted in the tetrasaccharide in a 61% overall yield.