Reena KumariAkash2024-06-112024-06-112024-06-05https://krishikosh.egranth.ac.in/handle/1/5810210373The present investigation "Purification and Characterization of Trypsin Inhibitor from germinating seeds of Leucaena leucocephala L." was done using ammonium sulphate precipitation and ion exchange chromatography on DEAE-Cellulose 52. Seven samples viz., Sl to S7 of Leucaena leucocephala were screened for the presence of trypsin inhibitor. Among all samples, S1 showed maximum trypsin inhibitor activity and S7 showed minimum trypsin inhibitor activity. The results confirmed 21.4% decline in trypsin inhibitor activity on the 5th day of seed germination. Further protein was purified to 5.03, 5.0 and 4.78 fold with a percent yield of 14.52, 14.0 and 13.98 from Sl, S2 and S3, respectively. The molecular weight of purified protein was found to be ~20 kDa. The purified trypsin inhibitor found to be heat stable up to 80℃ and showed resilience in the pH range of 4.0-10. The inhibitor was found to be susceptible to varying concentrations of reducing agents like DTT and β-mercaptoethanol, thereby indicating the role of disulphide bridges in maintaining its three dimensional structure and stability. The purified protein was found to be effective to decrease midgut protease of Pieris rapae. This stability of inhibitor across a broad pHrange (4-10), demonstrates its potential as an insecticidal protein againstLepidopteran and Coleopteran insects.EnglishThesis