The B4 lectin from Vicia villosa seeds interacts with N-acetylgalactosamine residues alpha-linked to serine or threonine residues in cell surface glycoproteins.

摘要: We have examined the carbohydrate binding specificity of B4 lectin from Vicia villosa seeds. The agglutinates Tn-exposed erythrocytes specifically and binds to these (1.4 X 10(6) sites/cell) with an association constant 4.2 10(7) M-1. concentrations saccharides glycopeptides defined structure which cause 50% inhibition were determined. N-Acetylgalactosamine is best monosaccharide inhibitor, causing at a concentration 0.04 mM. Other monosaccharides inhibit in following order decreasing potency: N-acetylgalactosamine greater than methyl-alpha-galactopyranoside p-nitrophenyl-alpha- or beta-galactopyranoside methyl-beta-galactopyranoside, galactose galactosamine mannose, N-acetylglucosamine. disaccharide Gal beta 1,3GalNAc causes 2.8 mM, similar that beta-galactopyranosides. Glycopeptides containing O-glycosidically linked oligosaccharide units are significantly more potent inhibitors alone. most glycopeptide inhibitor fetuin two alpha-linked units. This 0.00034 mM probably closely resembles site on erythrocytes.