Quantum-Chemical Structure-Activity Relationships in Carbamate Insecticides

Abstract

A non-empirical Quantitative Structure-Activity Relationship (QSAR) method is employed to analyze the reversible complex formation during the reaction of phenyl-N-methylcarbamates with the enzyme acetylcholinesterase. No common equation for the ortho, meta and para-substituted molecules could be obtained. A good description of the reversible complex formation is achieved by separating the molecules according to the position of the aromatic substituent. The introduction of a substituent orientation parameter helps account for the percentage of molecules attaining the proper orientation to interact with their partner. This parameter is useful in describing physical effects depending on the rotational partition function. A model for the carbamate-acetylcholinesterase reversible complex is proposed.