Chemical and enzymatic synthesis of high-affinity selectin ligands

Analogs of sialyl LewisX have been synthesized chemically using donors of modified sialic acids. The sialic acids were obtained enzymatically by an aldolase reaction. The sLex tetrasaccharides modified at C-2 of the GlcNAc moiety and at C-5 of the sialic acid residue were tested as inhibitors for E- and P-selectins. Up to 12-fold higher inhibitory potency was found for the lyso-derivative of sLeX compared to the parent compound.