Enzymatic fucosylations of non-natural acceptors with non-natural donor-sugars

Non-natural sialyl-lactosamine derivatives are treated with recombinant fucosyl-transferase VI in the presence of non-natural guanosine diphosphate-activated donor sugars. The biocatalyst transfers the non-natural donor sugars with the same regio- and stereospecificity as the parent fucose to the non-natural acceptors yielding sialyl-Lex-oligosaccharide libraries.