Enzymic properties of an N-acetylglucosaminide 3-alpha-L-fucosyltransferase of a wheat-germ agglutinin-resistant melanoma clone

A fucosyltransferase was solubilized by extraction with Triton CF‐54 from a wheat‐germ agglutinin‐resistant variant of mouse B16 melanoma. Through affinity chromatography on GDPhexanolamine–Sepharose a 44‐fold enrichment of its specific activity was obtained. Analysis of its specificity indicated that the enzyme is an N‐acetylglucosaminide 3‐α‐l‐fucosyltransferase, which is able to transfer fucose to oligosaccharides containing Gal(β‐4)GlcNAc and Gal(β‐4)Glc structures. The enzyme is activated by divalent cations and has a maximum of activity at pH 5. It is unable to transfer fucose to sialylated glycoproteins, 6‐α‐sialyllactose or 3‐α‐sialyllactose. As suggested by its precipitation in the presence of antibodies raised in rabbit against a soluble human milk N‐acetylglucosaminide 3‐α‐l‐fucosyltransferase, these two enzymes seem to be structurally related.