Protease activity and partial characterization of the trypsin-like enzyme in the digestive tract of the tropical sierra Scomberomorus concolor

Protease and trypsin-like activities of the digestive system of the tropical sierra Scomberomorus concolor were evaluated. Sierra digestive tract extracts hydrolyzed specific substrates for trypsin, chymotrypsin, and leucine aminopeptidase. At least eight bands of activity were observed by using SDS-PAGE. In PAGE and serine-inhibition assays, one fraction resembled bovine trypsin. An ammonium sulfate (40-60%) trypsin-like fraction displayed different inhibitions with tosyllys-chloromethyl ketone (96%) and soybean trypsin inhibitor (100%). Maximum activity was found using benzoyl-L-arginine-p-nitroanilide as substrate at pH 9.0 at 25°C and around 50°C at pH 7.8. The capacity of the trypsin-like fraction to work at different pHs (4, 7, and 9) at 25°C and different temperatures (0 and 40°C) at pH 7.8 were detected.