PURIFICATION AND CHARACTERIZATION OF A TUBER LECTIN FROM ALOCASIA-INDICA

A lectin from the tubers of Alocasia indica Schott has been purified b y affinity chromatography on asialofetuin-linked amino activated silic a beads. The bound lectin was eluted with 0.1 M glycine-HCl buffer, pH 2.5. The purified lectin yielded a single band on SDS-PAGE, pH 8.3, c orresponding to M(r) of 13 000. In polyacrylamide gel electrophoresis, pH 4.5, and gel exclusion chromatography, it also gave a single band and a single peak, respectively, with M(r) of 55 000. However, in poly acrylamide gel electrophoresis at pH 8.3, it revealed three bands. Thr ee peaks were obtained when the affinity purified lectin was applied o n a DEAE-5PW HPLC analytical column. As a haemagglutinin, this lectin was effective against animal but not human erythrocytes. The haemagglu tination activity is inhibited by asialofetuin only. The purified lect in is a glycoprotein with 1.47% carbohydrate content and has no metal ion requirement for its haemagglutinating activity. Alocasia indica wa s found to be mitogenic for human peripheral blood lymphocytes.