Exploring the substrate specificity of sialyl- transferases

Abstract: Twelve trisaccharide derivatives designed for detailed exploration of the acceptor specificity of sialyltransferases involved in the biosynthesis of N-glycans have been synthesized. These compounds include P-D-Galp- ( 1-4)-P-D-GlcpNAc- ( 1-2)-a-D-Manp- ( 1-O)(CH2)7CH3 and analogues containing structural variants of D-galactose. All trisaccharides were obtained by condensation of suitably modified glycosyl donors with a single disaccharide acceptor, thus limitating the number of reaction steps required. After deprotection, the compounds were employed to delineate the recognition characteristics of several natural and recombinant sialyltransferases