Purification of the blood groupH gene associated ?-2-l-fucosyltransferase from human plasma

Publisher Website
Google Scholar
Abstract
The α-2-l-fucosyltransferase in human plasma has been freed from α-3-l-fucosyltransferase activity and purified approximately 200,000-fold by a series of steps involving ammonium sulphate precipitation, hydrophobic chromatography on Phenyl Sepharose 4B and affinity chromatography first on GDP-adipate-Sepharose and then on GDP-hexanolamine-Sepharose. The purified α-2-l-fucosyltransferase had a Mr on gel filtration HPLC of 158,000 and showed optimal activity in the pH range 6.5–7.0. The enzyme transferred fucose equally well to Type 1 (Galβ1-3GlcNAc) and Type 2 (Galβ1-4GlcNAc) substrates but Type 3 (Galβ1-3GalNAc) structures were less efficient acceptors. Competition experiments indicated that a single enzyme species in the purified preparation was responsible for reactivity with the Type 1 and Type 2 structures. Thus the differences in conformation between the Type 1 and Type 2 disaccharides do not appear to influence the capacities of their terminal non-reducing β-d-galactosyl residues to function as acceptor substrates for the α-2-l-fucosyltransferase expressed by the blood groupH gene in haemopoietic tissue.