PURIFICATION AND CHARACTERIZATION OF 2 MAJOR LECTINS FROM VIGNA-MUNGO(BLACKGRAM)

Blackgram( Vigna mungo L. Hepper) seeds contain two galactose-specific lectins, BGL-I and BGL-II. BGL-I was partially purified into two mono meric lectins which were designated as BGL-I-1 (94 kDa) and BGL-I-2 (8 9 kDa). BGL-II is a monomeric lectin of 83 kdA. The purified lectins s ere associated with galactosidase activities. BGL-I-1 and BGL-II were copurified with alpha-galactosidase activity while BGL-I-2 was largely associated with beta-galactosidase activity. These lectins agglutinat e trypsin treated rabbit erythrocytes, but not the human erythrocytes of A, B or O groups. They were stable between pH 3.5 and 7.5 for their agglutination. The lectins did not show any metal ion requirement The y were inactivated at 50 degrees C. The lectin activity was inhibited by D-galactose (0.1 mM). The Scatchard plots of galactose binding to t hese lectins are nonlinear and biphasic corves indicative of multiple binding sites. The data show that the monomeric lectins have both lect in and galactosidase activities suggestive of a bifunctional protein.