Galactoside 3(4)-L-fucosyltransferase (FUT3)

May catalyze alpha-1,3 and alpha-1,4 glycosidic linkages involved in the expression of Vim-2, Lewis A, Lewis B, sialyl Lewis X and Lewis X/SSEA-1 antigens. Might be involved in blood group Lewis determination; Lewis-positive (Le(+)) people have an active enzyme while Lewis-negative (Le(-)) people have an inactive enzyme.

Also acts on the corresponding 1,4-galactosyl derivative, forming 1,3-L-fucosyl links. .