Abstract:

In order to obtain optimal conditions for the extraction of cathepsin B from Takifugu obscures, on the basis of
results of single-factor experiments, some extraction parameters affecting cathepsin B activity were firstly evaluated by
Plackett-Burman design, and then the main variables were optimized by response surface analysis. The results showed that
the optimal extraction conditions were as follows: material/liquid ratio 1:2.1, phosphate buffer pH 7.0, and ammonium
sulfate saturation 99.2%, and these three factors had significant influence on the enzyme activity. Under these conditions,
the predicted value of cathepsin B activity was 32.65 U/g and its experimental value was 32.52 U/g, suggesting that the
established model is feasible and can provide a theoretical basis for further studies on the extraction process of cathepsin B.

Key words: Takifugu obscures, cathepsin B, Plackett-Burman design, response surface analysis