Activation of Cockroach Acetylcholinesterase by Water-miscible Organic Solvents

Abstract

IT is common practice to treat insects with poisons dissolved in acetone or dioxane. Also, water-insoluble anti-cholinesterases are dissolved in organic solvents to determine their inhibition of acetylcholinesterase in vitro. While studying functional properties of acetylcholinesterase of the American cockroach¹, evidence was obtained that inclusion of acetone or some alcohols in a Warburg reaction mixture resulted in greater hydrolysis of acetylcholine. These results are given in Table 1, where 0.1 ml. of the organic solvents was included in a Warburg reaction mixture of salts, buffer, substrate and tissue homogenate, final volume, 2.7 ml. The increase in hydrolysis of acetylcholine was most striking in the presence of n-propanol and n-butanol. Further work showed that the optimal concentration of n-butanol for maximal hydrolysis of acetylcholine was 0.05 ml. in 2.7 ml. of reaction mixture. Acetone differed in this respect and optimal activity was obtained at 0.25 ml. of acetone in 2.7 ml. of reaction mixture.