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.