Synthesis of the milk oligosaccharide 2′-fucosyllactose using recombinant bacterial enzymes

Abstract The enzymatic synthesis of GDP-β- l -fucose and its enzymatic transfer reaction using recombinant enzymes from bacterial sources was examined. The GDP- d -mannose 4,6-dehydratase and the GDP-4-keto-6-deoxy- d -mannose 3,5-epimerase-4-reductase from Escherichia coli K-12, respectively, were used to catalyse the conversion of GDP-α- d -mannose to GDP-β- l -fucose with 78% yield. For the transfer of the l -fucose to an acceptor, we cloned and overproduced the α-(1→2)-fucosyltransferase (FucT2) protein from Helicobacter pylori. We were able to synthesise 2′-fucosyllactose using the overproduced FucT2 enzyme, enzymatically synthesised GDP- l -fucose and lactose. The isolation of 2′-fucosyllactose was accomplished by anion-exchange chromatography and gel filtration to give 65% yield.