Study on the protease and amylase of Hypophthalmichthy molitrix and Aristichthys nobilis.
The activity of protease and amylase in silver carp Hypophthalmichthys molitrix and big head carp Aristichthys nobilis were determined with the enzyme kinetic method. Results showed that both the 2 species had their protease activity in hepatopancreas higher than that in other organs, and not detected in bile. Among the 5 equal sections of intestine, the highest protease activity was noted in the section II. The silver carp had its amylase activity with a similar distribution, but the big head carp had its amylase activity the highest in the section I of intestine. The big head carp had its protease activity higher than that in silver carp in their respective organs, however, the difference was insignificant. The optimum pH for the presence of protease and amylase in the 2 species was 8.0-8.5 and 7.5, respectively. Cellulase activity was detected in the gut content but not in intestinal mucosa of silver carp.