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Only one bovine gene, corresponding to the human cluster of genes FUT3-FUT5-FUT6, was found by Southern blot analysis. The cognate bovine α(1,3)-fucosyltransferase shares 67.3, 69.0, and 69.3% amino acid sequence identities with human FUC-T3, FUC-T5, and FUC-T6 enzymes, respectively. As revealed by protein sequence alignment, potential sites for asparagine-linked glycosylation and conserved cysteines, the bovine enzyme is an intermediate between FUC-T3, FUC-T5, and FUC-T6 human enzymes. Transfected into COS-7 cells, the bovine gene induced the synthesis of an α(1,3)-fucosyltransferase enzyme with type 2 substrate acceptor pattern specificity and induced expression of fucosylated type 2 epitopes (Le^x and sialyl-Le^x), but not of type 1 structures (Le^a or sialyl-Le^a), suggesting that it has an acceptor specificity similar to the human plasma FUC-T6. However, no enzyme activity was detected …