Trypsin from the viscera of sierra (Scomberomorus sierra) was purified by affinity chromatography on Sepharose-4B coupled to soybean trypsin inhibitor and characterized with respect to its purity, sensitivity to temperature, pH and inhibition. Trypsin was purified from sierra viscera with 11.9-fold and 29.7% yield. The enzyme had a molecular weight of 25.4 kDa estimated by SDS-PAGE and two possible trypsin isoforms were observed in activity gels. Trypsin activity was strongly inhibited by soybean trypsin inhibitor and porcine trypsin inhibitor, showing a partial inhibition by a serine protease inhibitor. The optimal activity of the enzyme was observed at pH 9 and 60C with n-α-benzoyl-dl-arginine-p-nitroanilide as a substrate. The enzyme maintained more than 50% of its activity in temperatures up to 50C and within the pH range of 8–10 for a period of up to 2 h.
The potential applications of purified trypsin from tropical sierra fish viscera are those that are already in use for trypsin, such as an aid for hydrolysis of food proteins, as an aid in reducing viscosity of stickwater from fish processing plants, and in obtaining bioactive fractions from protein hydrolisates. Specific uses of this particular trypsin from tropical sierra could be those that comply with the optimum conditions at 60C and pH 9–10 or stability described in the results.