Study of the fucosyltransferase system in intestinal microsomes.

Fucosyltransferase activity of rat small intestine microsomes is solubilized by 0.5% Triton X-100. The solubilized activity can be purified up to 8,300-fold using DEAE-cellulose and affinity chromatography on GDP-Sepharose. At this step, chromatography on Sephadex G15 separates different specificities: N-acetylglucosaminide-alpha-(1,3)-fucosyltransferase acting on asialoserotransferrin, and galactoside-alpha-(1,2)-fucosyltransferase acting on O-glycans of asialofetuin. The use of small saccharidic acceptors also indicates the presence of a N-acetylglucosaminide-alpha-(1,4)-fucosyltransferase and of a very weak glucose-alpha-(1,3)-fucosyltransferase activity. These activities are tightly bound to concanavalin A-Sepharose, suggesting that they are supported by N-glycosylproteins.