Isolation and characterization protease enzyme from leguminous seeds

The present study was conducted to isolate and characterize the proteases from seven leguminous seeds: soybean, lentil, black gram, green gram, bengal gram, groundnut and pea bean. We elaborated the easy procedure for isolation of protease from leguminous seeds by using (NH4)2SO4 precipitation. The effect of pH and temperature of protease activity were determined. This study revealed that the protein concentration of crude extract ranged between 2.215 to 2.40 mg/ml in which groundnut was highest protein concentration (2.40 mg/ml) and lentil accounted was lowest concentration (2.21 mg/ml). The pH profile of proteases showed maximum specific activity at pH 7.5 to 9.0 with one main peak at pH 9.0. Among the seeds, bengal gram showed highest specific activity (0.007659 U/mg of protein) at pH 7.5 but lowest activity was observed in pea bean (0.001681 U/mg of protein) at pH 9.0. The temperature vs. specific and catalytic activity of all proteases relationship demonstrated a symmetrical distribution with one main peak and optimum at 37 o C except black gram which showed two main peaks at 37 o C and 70 o C respectively. The paper concludes that leguminous seeds can be source of proteases for industrial purposes.