Characterization of Ammonium Sulphate Fraction Tripsin Isolated from Intestine of Little Tuna

Abstract

Intestine is part of the digestive tract of fish having neutral pH. Thus, fish intestine is a potential source of typsin and can be an alternative source to the commercial trypsin enzyme derived from pork and cat-tle. This study was aimed to analyze the characteristics of the ammonium sulphates fraction of the trypsin enzyme from tuna intestine. The research began with the extraction of the trypsin enzyme from the little tuna intestine and followed up by fractionation using ammonium sulphates (0-80%). Optimum temperature and pH as well as effects of metal ions, stability to NaCl, optimum substrate and reaction kinetics were determined. Enzyme activity was measured using N-α-benzoyl-DL-arginine-p-nitroanilide (BAPNA). The results showed that the trypsin crude extract had an activity of 0.205 U / mL. The highest enzyme activity was found in the ammonium sulphates fraction of 40-50%. The enzyme worked optimally at 60°C and pH 9. Metal ions including ZnCl2 and CaCl2 inhibited trypsin activity, while MnCl2, CuCl2, and NaCl increased trypsin activity. Trypsin activity was stable at 5-30% NaCl. The enzyme had a Vmax value of 0.42 mmol/s and a Km value of 1.12 mM.