Purification and Some Properties of the Basic Lectin from Winged Bean Seeds

Abstract

Winged bean basic lectin was purified by affinity chromatography on p-aminophenyl-β-D-galactopyranoside bound Sepharose 4B. The purified lectin was homogeneous on polyacrylamide gel electrophoresis, isoelectric focusing, and gel filtration. The molecular weight of the lectin was 53,000±1,800 by gel filtration, SDS-polyacrylamide gel electrophoresis gave a single component of molecular weight of 27,000, suggesting that the lectin was a dimer. The isoelectric point was pH 8.62 ± 0.17. The basic lectin was rich in aspartic acid and threonine, and poor in sulfur-containing amino acids. The basic lectin agglutinated both trypsinized and untreated human erythrocytes; it bound highest with type A, somewhat lower with types B and AB, and negligibly with type O erythrocytes. Among the tested sugars, D-galactose and N-acetyl-D-galactosamine were active in inhibiting the hemagglutination. In contrast, the determinant sugars in blood group O, such as l-fucose and N,N’-diacetylchitobiose, were entirely inactive, confi...