A rat ganglioside GM1-specific alpha 1}2fucosyltransferase is disclosed. Nucleotide sequences of a rat ganglioside GM1-specific alpha 1}2fucosyltransferase, amino acid sequences of its encoded protein (including peptide or polypeptide), and derivatives thereof are described. Also described are fragments (and derivatives and analogs thereof) which comprise a domain of rat ganglioside GM1-specific alpha 1}2fucosyltransferase with catalytic activity. Methods of production of rat ganglioside GM1-specific alpha 1}2fucosyltransferase and derivatives and analogs thereof (e.g. by recombinant means) are provided. Methods of inhibiting the function of rat ganglioside GM1-specific alpha 1}2fucosyltransferase (e.g. by means of antisense RNA) are provided. Methods of commercial scale use of the rat ganglioside GM1-specific alpha 1}2fucosyltransferase in the production of fucosyl-saccharide compositions are described. Applications of these compositions, e.g. as additives for human nutritive compositions or immunotherapeutics for cancer, are disclosed.