Trypsin and Chymotrypsin Activity in Developmental Stages of <i>Acanthoscelides obtectus</i> (Say) and Screening <i>Phaseolus vulgaris</i> Cultivars for Inhibitory Effect on Bovine Pancreatic Proteases

The present study aims to examine trypsin and chymotrypsin levels in Acanthoscelides obtectus (Say), a devastating pest of kidney beans and evaluate the efficacy of protease inhibitors from Phaseolus vulgaris cultivars against these enzymes of bovine origin. Trypsin and chymotrypsin were extracted from different developmental stages of A. obtectus and their activities were measured spectrophotometrically. The enzyme activity for both enzymes increased from 2nd instar to 3rd instar and showed decreasing trend from 4th instar to adults. The highest enzyme activity was observed in the third instar grub, with trypsin activity of 2.74±0.08 U/mg and chymotrypsin activity of 15.41± 2.18 U/mg. Additionally, ten cultivars of P. vulgaris were screened for their inhibitory potential against pure bovine pancreatic trypsin and chymotrypsin. The results indicated that the BASPA and PLB14-I cultivars were most effective, showing maximum inhibition of 84% against trypsin and 93% against chymotrypsin respectively. Moreover, successful inhibition of bovine protease offers insight into how inhibitors derived from plant sources might inhibit insect proteases in vivo using a similar approach.