CHARACTERISTICS OF TWO TRYPSIN ISOZYMES FROM THE VISCERA OF JAPANESE ANCHOVY (ENGRAULIS JAPONICA)

Two isozymes of trypsin (TR-I and TR-II) were purified from the viscera of Japanese anchovy (Engraulis japonica) 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-I, IVGGYECQAHSQPHTVSLNS, and TR-II, IVGGYECQPYSQPHQVSLDS, were found. Both TR-I and TR-II had maximal activities at around pH 8.0 and 60C for hydrolysis of Nα-p-tosyl-L-arginine methyl ester hydrochloride. The TR-I and TR-II were unstable at above 50C and below pH 5.0 and were stabilized by calcium ion.