PURIFICATION AND CHARACTERIZATION OF A LECTIN FROM SEEDS OF THE WINGED BEAN, PSOPHOCARPUS-TETRAGONOLOBUS (L)DC

A lectin from seeds of the winged bean, Psophocarpus tetragonolobus (L.)DC, has been purified to homogeneity by affinity chromatography on a Bio-Gel lactobionate adsorbent. The lectin is rich in acidic amino acids, and after isoelectric focusing in polyacrylamide gel, appeared as a single band of pI 5.5. The molecular weight of the lectin is 46 000 ± 2000 as determined by analytical ultracentrifugation. Dodecyl sulfate gel electrophoresis detected a single type of subunit with a molecular weight of 29 000 ± 3000. The lectin has specificity for receptors containing D-galactose and agglutinates trypsinized human red blood cells of all three ABO types. Of the tested inhibitors of hemagglutination caused by winged bean lectin, p-nitrophenyl-β-d-galactoside was the most potent. Lactose was the most active oligosaccharide tested, and other oligosaccharides containing α-linked d-galactose were much less inhibitory. © 1979.