Kinetic constants Km and kcat of the purified Z. ophiocephalus trypsin were determined using Lineweaver–Burk plots. The Km and kcat of the purified enzyme, using BAPNA, were 0.312 mM and 2.03 s−1, respectively, and were close to those reported for trypsins from bigeye snapper (Pricanthus macracanthus) [36] and silver mojarra . The catalytic efficiency (kcat/Km) of Z. ophiocephalus trypsin, 6.51 s−1mM−1, was close to trypsins from silver mojarra and bigeye snapper