PURIFICATION OF A LECTIN FROM PARKIA-JAVANICA BEANS

A lectin was extracted from Parkia javanica beans and purified by chro matography. The purified lectin showed two forms of proteins, one majo r and one faint band, both in non-denaturing PAGE and SDS-PAGE. Both o f them appeared to be single polypeptide chains with M(r), determined by SDS-PAGE, of 47 900 and 45 700. The purified lectin could agglutina te red blood cells of rabbit (68 267 unit mg(-1) protein) and rat (267 unit mg(-1) protein), but could not agglutinate red cells of human, s heep or goose. Its hemagglutinating activity was completely inhibited by methyl-alpha-D-mannosamine and mannose at 5 mM. Ca2+, Mn2+ and Mg2, but neither EDTA nor EGTA, were effective activators of the purified lectin. The K-0.5 of Ca2+, Mn2+ and Mg2+ was 5, 17 and 13 mM, respect ively. The optimal pH for hemagglutination was 7. The purified lectin was stable in pH 7-10 but labile at temperatures over 50 degrees.