The activity of the crude enzyme wa

The activity of the crude enzyme was determined at different pH values (5.0–12.0). As shown in Fig. 2a, two activity peaks were observed at pH 6.0 and 10.0. The enzyme preparation was highly active between pH 8.0 and 11.0, with an optimum at pH10.0. The relative activities at pH 9.0, 11.0, and 12.0 were about94%, 69%, and 39%, respectively, of that at pH 10.0. The opti-mum pH of S. scrofa proteases was similar to those of Colossomamacropomum proteases (Esposito et al., 2009a) and Lithognathusmormyrus proteases (El Hadj-Ali et al., 2011).