Use of recombinant enzymes for preparing GDP-L-fucose and fucosylated glycans

Use of recombinant enzymes for the preparation of GDP-L-fucose and fucosylated glycans is disclosed. GDP-L-fucose functions as a fucose donor in the biosynthetic route leading to the fucosylated glycans, which have therapeutic utility. A process for preparing GDP-L-fucose and fucosylated glycans, and means useful in the process are provided. Said means include enzymes, chimeric enzymes, DNA sequences, genes, vectors and host cells. An assay for the determination of GDP-fucose and fucosyltransferase, and a test kit therefore are also provided.