Lactose as affinity eluent and a synthetic sulfated copolymer as inhibitor, in conjunction with synthetic and natural acceptors, differentiate human milk Lewis-type and plasma-type alpha-L-fucosyltransferases.

Human milk Lewis-type (alpha 1,3/4) fucosyltransferase (FT) was separated from the plasma-type by chromatography on bovine IgG glycopep-Sepharose using lactose as the selective eluent and further purified on a column of Sephacryl S-100 HR. The alpha 1,3-FT activity towards 2'-fucosyllactose was found to be associated with alpha 1,4-FT activity. The inherency of N-acetyl-glucosaminide alpha 1,3-L-FT activity in the Lewis-type FT was shown by a) the emergence of both alpha 1,3- and alpha 1,4-FT activities from the Sephacryl S-100 HR column in the same position; b) the inhibition of the alpha 1,3-FT activity in the Lewis-type FT by alpha 1,4-FT specific inhibitor namely a copolymer from 3-sulfoGal beta 1,3GlcNAc beta-O-Allyl and acrylamide; c) the inhibition of alpha 1,4 activity in the Lewis-type FT by alpha 1,3-FT specific acceptor. Fetuin triantennary sialoglycopeptide, the corresponding asialo glycopeptide, and bovine IgG diantennary glycopeptide served as acceptors for both FTs, the Lewis-type FT being far more active than the plasma type FT towards the triantennary sialoglycopeptide.