Isolation of a new trypsin inhibitor from the faba bean (Vicia faba cv. Giza 843) with potential medicinal applications

A new 15-κda bowman-birk type trypsin inhibitor (termed vfti-g1) was isolated from the seeds of faba bean (vicia faba cv. giza 843) using cation exchange chromatography on an sp-sepharose column,anion exchange chromatography on q-sepharose and mono q columns,and finally size exclusion chromatography on a superdex 75 column. vfti-g1 manifested significant antiproteolytic activity against trypsin (5761 baee units/mg,ki 20.4 × 10-9 m),but only a slight chymotrypsin inhibitory activity (< 10 btee units/mg). the suitable environment to sustain its trypsin inhibitory activity was at temperatures below 60 °c and at ph 7. its trypsin inhibitory activity was inhibited by the reducing agent dithiothreitol in a dose-dependent manner,indicating the significance of intact disulfide bonds to the trypsin inhibitory activity. it inhibited hiv-1 reverse transcriptase (rt) activity with an ic 50 of about 0.76 μm. furthermore,vfti-g1 showed specific antiproliferative activity toward hepg2 hepatoma cells by inducing chromatin condensation and cell apoptosis. the hiv-1 rt inhibitory activity of vfti-g1 and its specific antiproliferative activity toward hep g2 cells may find medical applications. © 2011 bentham science publishers ltd.