Isolation of a novel N-acetyl-D-lactosamine specific lectin from Alocasia cucullata (Schott.)

An N-acetyl-D: -lactosamine (LacNAc) specific lectin from tubers of Alocasia cucullata was purified by affinity chromatography on asialofetuin-linked amino activated silica. The pure lectin showed a single band in SDS-PAGE at pH 8.8 and was a homotetramer with a subunit molecular mass of 13.5 kDa and native molecular mass of 53 kDa. It was heat stable up to 55 degrees C for 15 min and showed optimum hemagglutination activity from pH 2 to 11. The lectin was affected by denaturing agents such as urea (2 M: ), thiourea (2 M: ) and guanidine-HCl (0.5 M: ) and did not require Ca2+ and Mn2+ for its activity. It was a potent mitogen at 10 microg/ml towards human peripheral blood mononuclear cells with 50% growth inhibitory potential towards SiHa (human cervix ) cancer cell line at 100 microg/ml.