LAUSR

Plant protease inhibitors are defense molecules against pests, predators and pathogens. We purified and characterized a new 14 kDa protease inhibitor from the seeds of Spatholobus parviflorus by ammonium sulfate precipitation, ion exchanges chromatography, trypsin-affinity chromatography and Ni-IMAC affinity chromatography. The purified inhibitor at a concentration of 0.1 µg/µl inhibited gut protease activity of Spodoptera mauritia , a pest of paddy, to the extent of 50%. The yield of the inhibitor was 1 mg/100 gm of seed and achieved 92 fold purification compared to crude extract. LC–MS/MS analysis revealed that this new inhibitor is a Kunitz-type serine protease inhibitor. Inhibitor is stable up to a temperature of 80 °C and optimum pH is 8.0. The high-temperature stability and retention of inhibition in the alkaline pH range, the pH range in the larval gut of lepidopteran pests, make it a potential candidate for application in pest control.