Novel method for quantifying α(1→3)-L-fucosyltransferase activity in serum

Abstract

A novel method has been developed to quantify alpha(1----3)-L-fucosyltransferase activity in human sera by applying a sandwich-type immunoradiometric assay. H type 2 trisaccharide (6Fuc alpha 1----2Gal beta 1----4GlcNAc) covalently attached to bovine serum albumin (BSA) was used as an acceptor and incubated with serum samples in the presence of guanosine diphosphate-fucose. The resulting product, Y tetrasaccharide (Fuc alpha 1----2Gal beta 1----4[Fuc alpha 1----3] GlcNAc beta-BSA), was detected by a sequential use of anti-BSA antibody-coated bead and 125I-labeled anti-Y antibody. Inter- and intra-assay CVs for alpha(1----3)-L-fucosyltransferase were both less than 4%, and the results of the dilution linearity and analytical recovery studies were satisfactory. Using the present assay method, we measured alpha(1----3)-L-fucosyltransferase in serum from patients with benign and malignant gastric disorders and in healthy subjects. The detection rate of alpha(1----3)-L-fucosyltransferase for cancer was apparently higher than that of carcinoembryonic antigen measured in the same samples, particularly in the early clinical stage; indeed, no correlation was observed between the concentrations of the two potential markers. The results indicate that the present assay method seems to be excellent for the determination of serum alpha(1----3)-L-fucosyltransferase activity and useful for the detection of cancer-associated increases of the enzyme activity at the early stage of gastric cancer.