2 KINDS OF NEUTRAL SERINE PROTEINASES IN SALTED MUSCLE OF ANCHOVY, ENGRAULIS-JAPONICA

Two kinds of proteinases, type-I and type-II, were purified or partial ly purified from salted muscle of anchovy, Engraulis japonica, Mol. wt s. of type-I and type-II proteinases were estimated to 25,000 and 37,0 00, respectively, on electrophoretic analysis. Both proteinases strong ly hydrolyzed synthetic tri or tetrapeptide substrates specific to try psin, alpha-thrombin, and an activated protein C, while they hardly hy drolyzed Arg-MCA and benzoyl Arg-MCA derivatives. The proteinases were inhibited by common trypsin inhibitors. Optimal pH for the proteinase activities were pH 6.8 (type-I) and pH 7.0 to 7.5 (type-II), and the proteinases showed the highest activities at 45 degrees C (type-I) and 50 degrees C (type-II), The N-terminal amino acid sequence of type-I proteinase, I-1-V-2-(3)G-(4)G... (29 residues were identified), was si gnificantly similar to sequences of trypsins and tryptases. Based on t hese findings, both proteinases were presumed to be kinds of tryptases in E. japonica muscle.