Biochemical Insights into Pigeon Pea Protease Inhibitors for Agricultural Pest Control

Basically, plant uses a variety of bioactive secondary metabolites & defensive proteins to defend themselves against herbivores & fungal diseases. Protease inhibitors / Antiprotease, which can act as insect antifeedant proteins are among these defence proteins. These inhibitors are natural substances present in plants which act by changing the conformation of enzyme proteases present in insect gut thereby effect on insect digestive system; we can call this as a natural defence system of plants against insects. In this research work i.e. on Pigeon pea, around 14% to 100% loss in the farmer’s production has been observed due to insect pest attack. So by epistemology point of view, I thought to extract this natural anti -protease compounds from plants & use it as a natural defendant against insects that attack crop. Thus, total protease inhibitors were extracted using 0.1M Sodium Phosphate buffer (pH 7.5). Protease inhibitor was partially purified to homogeneity by employing conventional protein purification techniques such as Ammonium sulphate precipitation and Dialysis process. Further Partially purified proteins were quantitatively analyzed using Lowry’s Method. Among all the dialyzed fractions (10% to 100%), the fraction saturated with 60% Ammonium sulfate precipitation salt shown highest amount of protein i.e. 4924ug. Pigeon pea seed samples underwent SDS-PAGE (15%) to determine the molecular weights of the proteins. The samples exhibited distinct bands within the range (245–11 kDa), indicating differences in molecular weight due to the extraction process, which resulted in high-molecular-weight (HMW) peptides. The SDS-PAGE analysis further demonstrated the formation of low-molecular-weight (LMW) peptides with masses below 12 kDa. Pigeon pea seeds also have the ability to inhibit trypsin activity. These inhibitors can inhibit up to 59% of trypsin activity. Among all fractions, F6 (60%) showed the highest inhibitory effect on trypsin, whereas fraction F2 (20%) had the lowest inhibition. Similarly total activity and yield percentage in fraction 60% was found to be 4038 umol/min/ml and 83.25 % respectively.