Isolation and characterization of a lectin from Erythrina variegata (Linn) var. Orientalis seed.

Erythrina variegata lectin was purified by affinity chromatography with lactose-Sepharose 6B.The purified lectin was homogenous on polyacrylamide gel electrophoresis, immunoelectrophoresis, and Sephadex G-150 gel filtration.The molecular weight of the lectin was 60,000 by the gel filtration, and SDS-polyacrylamide gel electrophoresis gave a single band at a position corresponding to the molecular weight of 29,000, indicating that the lectin is a dimer composed of two identical subunits.The lectin was a glycoprotein with its neutral sugar content being 9 %.It contained high amounts of acidic and hydroxy amino acids, a low amount of methionine, and no cysteine.This lectin agglutinated human erythrocytes of O type at a concentration of 4 /ig/ml, which was inhibited most potently by pnitrophenyl-/*-D-galactopyranoside among the sugars tested, suggesting the importance of the hydrophobic contribution of the aromatic region in the sugar binding-activity.Galactose and its related sugars were also inhibitory but to lesser extents.