Characteristics of trypsins from the viscera of true sardine (Sardinops melanostictus) and the pyloric ceca of arabesque greenling (Pleuroprammus azonus)

Trypsins, TR-S and TR-P, from the viscera of true sardine (Sardinops melanostictus) and from the pyloric ceca of arabesque greenling (Pleuroprammus azonus), respectively, were purified by gel filtration and anion-exchange chromatography. Final enzyme preparations were nearly homogeneous in sodium dodecyl sulfate–polyacrylamide gel electrophoresis (SDS–PAGE) and the molecular weights of both enzymes were estimated to be 24,000 Da by SDS–PAGE. The N-terminal amino acid sequences of the TR-S, IVGGYECKAYSQPWQVSLNS, and TR-P, IVGGYECTPHTQAHQVSLNS, were found. The TR-S and TR-P had maximal activities at around pH 8.0 for hydrolysis of Nα-p-tosyl-l-arginine methyl ester. Optimum temperature of the TR-S and TR-P were 60 and 50 °C, respectively. The TR-S and TR-P were unstable at above 50 and 30 °C, respectively, and below pH 5.0. Both TR-S and TR-P were stabilized by calcium ion.