The expression in the E.coli strain BL21(RB791) of the wild-type gene fucA1 and of the mutant genes fucA1 A [previously named FrameFuc in (24) ], fucA1 B , fucA1 sm and fucA1 tm as fusions of glutathione S-transferase (GST) and the purification of the recombinant proteins were performed as reported previously (23) . The nomenclature used in this paper for the different a-fucosidase genes is listed in Table 1 .