A lectin with anti-HIV-1 reverse transcriptase, antitumor, and nitric oxide inducing activities from seeds of Phaseolus vulgaris cv. extralong autumn purple bean.

Lectins/hemagglutinins are a class of sugar-binding proteins which agglutinate cells and/or precipitate glycoconjugates. They occur widely in plants but manifest significant differences in activities, which means only a few of them own exploitable potentials. The objective of this study was to find and characterize a multifunctional plant lectin with high potential values in food chemistry and medicine. A 60-kDa lectin from Phaseolus vulgaris L. cv. Extralong Autumn Purple Bean (EAPL) was purified by liquid chromatography, and the sequence of its first 20 N-terminal amino acids was ANEIYFSFQRFNETNLILQR. It was galactose-specific and manifested hemagglutinating activity toward erythrocytes of rabbit, rat, mouse, and human ABO blood types. EAPL manifested anti-HIV-1-RT activity, and it could inhibit the proliferation of human tumor cells by inducing the production of apoptotic bodies. The nitric oxide-inducing activity of EAPL may find application in tumor therapy.