Effect of Protease Inhibitors on Autolysis of Carp Muscle Homogenate

Abstract

To asist the search of proteinases which participate in fish muscle autolysis, we investigated the effect of protease inhibitors on the autolysis. The autolysis was done in the presence of 3 m_M NaN₃ at 37°C. The degree was determined by the colorimetric quantitative assay of 5% trichloroacetic acid soluble fraction after the autolysis and by the qualitative method of comparing electrophoretic patterns. In this study we used muscle homogenate instead of muscle block from the necessity of mixing inhibitor. Though the autolysis of homogenate proceeded faster than that of block, it was considered to reflect roughly the autolysis of muscle block. The effects of inhibitor were similar in the quantitative and the qualitative methods. Soybean trypsin inhibitor, PCMB, and pepstatin had no effect, but EDTA tended to inhibit. This result suggested the participation of metallo proteinase in the autolysis. But CaCl₂ had no effect. Moreover, the effect of leupeptin suggested the participation of serine or systeine proteinase. Though iodoacetic acid showed a remarkable effect, it is still not clear whether the effect depends on proteinase.