Effect of malathion on kinetic parameters of acetylcholinesterase (EC 3.1.1.7) in vitro

Abstract

Kinetic analysis of the interaction of malathion with camel erythrocyte acetylcholinesterase was investigated in the present study. The Michaelis-Menten constant (K(m)) for the hydrolysis of acetylthiocholine iodide (ASCh) was found to be 53.15 μM and the V(max) was 0.287 μmol/min/mg protein. The K(mapp) and V(maxapp) were both decreased by increased malathion concentration. Dixon as well as Lineweaver-Burk plots and their secondary replots indicated that the nature of the inhibition was of the pure uncompetitive type with K(i) value estimated as 102.1 ppm. The K(iapp) decreased while V(maxiapp) increased by an increased concentration in ASCh.