Abstract

We report a chemo-enzymatic transglycosylation synthesis of the 4-methylumbelliferyl glycoside of a complex-type oligosaccharide substrate for core fucosylation. We demonstrate the use of the glycoconjugate in a newly developed enzyme assay to probe the activity and inhibition of fucosyltransferase VIII, which catalyzes the core fucosylation of N-glycans found on eukaryotic glycoproteins. In our assay, the fucosyltransferase VIII reaction is coupled to a specific glycosidase enzyme, allowing to distinguish an unmodified 4-methylumbelliferyl oligosaccharide probe from the fucosylated probe. Our results demonstrate that the assay is very sensitive and specific to the detection of enzymatic activity, while also enabling the identification of potential fucosyltransferase VIII inhibitors.