Simple method to purify milligram quantities of the galactose-specific lectin from the leaves of Bauhinia monandra

Leaves of Bauhinia monandra Kurz. (pata-de-vaca, pulse) contain a relativel y high concentration of a galactose-specific lectin (BmoLL). More than 2 mg of BmoLL were obtained from 5 g of leaf powder when a 10% (w/v) extract wa s submitted to 60% ammonium sulphate fractionation followed by guar gel aff inity chromatography. The purified lectin ran slowly as a single broad band on non-denaturing electrophoresis. Under denaturing and reducing condition s, it appeared as a major subunit of apparent molecular weight 33 kDa, posi tive to carbohydrate staining, and a non-glycosylated polypeptide (26 kDa), Column fractions containing the peak of BmoLL eluted from the affinity chr omatography, each containing the 33 and 26 kDa polypeptides. The highest ag glutination activity of BmoLL was found with glutaraldehyde-treated rabbit erythrocytes; fresh and glutaraldehyde-treated human erythrocytes of blood groups B and AB were also agglutinated,whereas those from groups A and O we re not. Copyright (C) 2000 John Wiley & Sons, Ltd.