Recombinant α-1,3-galactosyltransferase (α1,3GalT) from bovine origin expressed in E. coli enables in vitro galactosylation of glycoproteins. The enzyme catalyzes the transfer of galactose from UDP-galactose to biantennary N-glycans with terminal galactose residues, forming α-1,3 linkages. Available only upon request. 50 EqU are suitable for the in vitro galactosylation of 1 mg glycoprotein, 500 EqU for 10 mg.