EXPLORING THE SUBSTRATE-SPECIFICITY OF SIALYLTRANSFERASES

Twelve trisaccharide derivatives designed for detailed exploration of the acceptor specificity of sialyltransferases involved in the biosynt hesis of N-glycans have been synthesized. These compounds include beta -o-GlcpNAc-(1-2)-alpha-D-Manp-(1-0)(CH2)(7)CH3 and analogues containin g structural variants of D-galactose. All trisaccharides were obtained by condensation of suitably modified glycosyl donors with a single di saccharide acceptor, thus limitating the number of reaction steps requ ired. After deprotection, the compounds were employed to delineate the recognition characteristics of several natural and recombinant sialyl transferases.