Purification of a lectin from Parkia javanica beans

A lectin was extracted from Parkia javanica beans and purified by chromatography. The purified lectin showed two forms of proteins, one major and one faint band, both in non-denaturing PAGE and SDS-PAGE. Both of them appeared to be single polypeptide chains with M r , determined by SDS-PAGE, of 47900 and 45700. The purified lectin could agglutinate red blood cells of rabbit (68267 unit mg −1 protein) and rat (267 unit mg −1 protein), but could not agglutinate red cells of human, sheep or goose. Its hemagglutinating activity was completely inhibited by methyl-α- D -mannosamine and mannose at 5 mM. Ca 2+ , Mn 2+ and Mg 2+ , but neither EDTA nor EGTA, were effective activators of the purified lectin. The K 0.5 of Ca 2+ , Mn 2+ and Mg 2+ was 5,17 and 13 mM, respectively. The optimal pH for hemagglutination was 7. The purified lectin was stable in pH 7–10 but labile at temperatures over 50°.