어류 알의 Protease Inhibitor 활성 분포

Abstract

To identify and examine the distribution of proteolytic inhibitory activity in crude extracts from fish eggs, and to determine the applicability of these protease inhibitors as anti-degradation agents in surimi-based products and fish meat, we compared the inhibitory activities of various extracts from fish eggs to those of commercial proteases, such as trypsin and papain. We used the optimal conditions for the screening of trypsin activity: 30 ug/uL of 0.1% trypsin and 0.6 mM Na-benzoyl-L-arginine-p-nitroanilide (BAPNA) with a pH of 8.0 at 40℃ for 60 min. The activities of papain and four commercial proteases were investigated after mixing with 100 ug/uL enzymes and 0.3% casein with a pH of 8.0 at 40℃ for 60 min. We performed a screening assay to detect the inhibitory activity (%) of crude extracts from eight species of fish eggs against the target proteases trypsin and papain. The assay revealed a wide distribution of trypsin and papain inhibitors in fish eggs. The specific inhibitory activities (11.6–28.6 U/mg) of crude extracts from fish eggs against trypsin and BAPNA substrate were higher than that (0.64 U/mg) of egg whites, used as a commercial inhibitor. The inhibitory activities of crude extracts from fish eggs against trypsin, and of egg whites against casein substrate (1.94–4.51 U/mg), were higher than those of papain (0.24–1.57 U/mg) and commercial protease (0.04–0.32 U/mg). The extracts from fish eggs were rich in protease inhibitors that exhibited strong inhibitory activity against trypsin, a serine protease, and papain, a cysteine protease.