Abstract: Based on single-factor test,the central composite design was performed on three levels of the factors including incubation time,incubation temperature and pH,and the quadric regression model for activity conditions(the above three factors) of the acetylcholinesterase(AChE) was established,which was extracted from crucian brain,liver or muscle. The model was fitted well and the optimum combination was obtained by response surface analysis. Results indicated that incubation time,incubation temperature and pH significantly affect the activity of AChE. For brain AChE,they are 35 min,32 ℃ and 7.6 respectively. For live AChE,they are 28 min,30 ℃ and 7.6 respectively. For brain AChE,they are 31 min,31 ℃ and 7.6 respectively.

Key words: crucian, acetylcholinesterase, central composite design