Background.

Several studies have addressed the characterization of various digestive enzymes, which is essential to understanding the types, modes of action, and level of activity of these enzymes.

Goals:

The partial characterization of the digestive proteases was studied in fat snook juveniles (Centropomus parallelus, Poey 1869).

Methods:

Characterization was performed using electrophoretic and biochemical techniques.

Results:

Acidic proteases activity (stomach) is higher than alkaline proteases activity (intestine); also, chymotrypsin activity was superior to the trypsin activity. The optimal pH was 2 for stomach proteases with high stability in a wide range of pH 2-8, while the intestinal proteases showed two peaks with activity at pH 8 and 10 with stability at a pH of 8-12. Optimal temperatures were obtained between 45 to 55 °C for stomach and intestine proteases, respectively. Using proteases inhibitors, the presence of an aspartic protease (pepsin) was tested from stomach extracts and diverse serine proteases from intestine extracts. The zymograms showed 5 bands with alkaline proteolytic activity (79.5, 48.9, 37.0, 29.0, and 22.5 kDa), which were highly inhibited with PMSF, SBT1, and ovalbumin.

Conclusions.

C. parallelus is considered to have a high digestive capacity similar to those reported for other strictly carnivorous marine fish.