(210j) Interaction of Acetylcholinesterase with Phorate

Detection of residual organophosphates in food is of paramount importance in current scenario. Biosensors for pesticide detection may be developed on solid surfaces by monitoring the interaction of acetylcholinesterase with pesticides. Acetylcholinesterase is a hydrolytic enzyme which hydrolyzes acetylcholine, a neurotransmitter, into choline and acetate. This enzyme gets inhibited in the presence of pesticides. Utilizing this property, protein based sensor on solid surfaces may be developed. The interaction studies were carried out on silica surface using acetylcholinesterase and phorate, an organophosphate. Self-assembled monolayer was created by immobilization of enzyme on silica surface and further pesticide is allowed to interact with adsorbed protein. Binding of immobilized protein and phorate on surface was evaluated in terms of the mass and thickness change of surface using quartz crystal microbalance which is calculated from frequency and dissipation factor change using Sauerbrey equation. Low value of dissipation factor (∆D) corresponds to stronger binding of pesticide with protein. The nature of chemical reaction between acetylcholinesterase and phorate was analyzed by the stoichiometry and energy released. The interaction study was carried out at low phorate concentration of 5 ppm of phortae. These findings helps in the development of protein based pesticide detection sensor so as to provide user friendly technique for detection in raw food samples.

Keywords: Acetylcholinesterase, ITC, pesticide, QCM.

References:

1. Singh, A. K. et al., 1999 Development of sensors for direct detection of organophosphates. Part I: immobilization, characterization and stabilization of acetylcholinesterase and organophosphate hydrolase on silica supports. Biosensors & Bioelectronics. 14:703–713.