Expression of a recombinant human glycosyltransferase from a synthetic gene and its utilization for synthesis of the human blood group B trisaccharide.

A 1034-bp synthetic gene encoding the human blood group B glycosyltransferase, which catalyzes the transfer of galactose from UDP-Gal to Fuc alpha(1-2)Gal beta-OR to give the blood group B determinant Gal alpha(1-3)[Fuc alpha(1-2)]Gal beta-OR (where R is a glycoprotein or glycolipid), has been expressed in Escherichia coli by replacing its membrane-anchoring domain with an ompA bacterial secretory signal. The active enzyme was purified from the periplasm using UDP-hexanolamine affinity chromatography and used in the synthesis of preparative amounts of the human blood group B trisaccharide antigen. The substrate specificity and kinetics of the recombinant enzyme were comparable to the enzyme from human sera. Thus we have achieved the construction of a completely synthetic glycosyltransferase gene and its successful expression.