Purification and characterization of a Ca2+-dependent novel lectin from <i>Nymphaea nouchali</i> tuber with antiproliferative activities

A lectin (termed NNTL) was purified from the extracts of Nymphaea nouchali tuber followed by anion-exchange chromatography on DEAE-cellulose, hydrophobic chromatography on HiTrap Phenyl HP and by repeated anion-exchange chromatography on HiTrap Q FF column. The molecular mass of the purified lectin was 27.0 ± 1.0 kDa, as estimated by SDS/PAGE both in the presence and in the absence of 2-mercaptoethanol. NNTL was an o-nitrophenyl β-D-galactopyranoside sugar-specific lectin that agglutinated rat, chicken and different groups of human blood cells and exhibited high agglutination activity over the pH range 5-9 and temperatures of 30-60 °C. The N-terminal sequence of NNTL did not show sequence similarity with any other lectin and the amino acid analysis revealed that NNTL was rich in leucine,…