Computational Studies on the Interaction of Organophosphorus Pesticides with Acetylcholinesterase and Butyrylcholinesterase: Quantum Chemical Cluster Model and HSAB Approaches

In the present study, the interaction between organophosphorus pesticides and cholinesterase enzymes was investigated by quantum chemical cluster model and hard-soft acid-base (HSAB) approaches. The computational results of the equilibrium structure and reaction enthalpy were used to decipher the mechanism of organophosphorus pesticides coumaphos, dicrotophos, phorate, and terbufos, which interacted with the molecular cluster models of acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) enzymes. In addition, the HOMO-LUMO energy gap and the HSAB descriptors prove that AChE has outstanding electron acceptability, which is suitable as a biosensing material. In terms of the calculated electronic spectrum, because the energy level of the ground state and the excited state are changed after adding pesticides with enzymes, a significant red shift phenomenon will occur.