SOL-GEL-ENTRAPPED CHOLINESTERASES - A MICROTITER PLATE METHOD FOR MONITORING ANTICHOLINESTERASE COMPOUNDS

Herein is reported the successful entrapment of three esterase enzymes within silica, by means of the sol-gel process. The enzymes were acet ylcholinesterase (AChE) from electric eel (ee), AChE from bovine eryth rocytes (er), and butyrylcholinesterase (BChE) from horse serum. Enzym e entrapment was carried out in a novel configuration by casting the d oped sol-gel material in 96-well microtiter plates. The study determin ed the apparent kinetics of the activity and inhibition of the three e ntrapped enzymes and elucidated the optimal sol-gel matrix composition and preparation procedure. The enzyme mode of action within the sol-g el matrix was compared with that obtained in solution, under various e xperimental conditions. The activity of entrapped ee-AChE was found to depend on the concentration of the entrapped enzyme and on the sol-ge l preparation procedure and composition. It was found that whereas the activity of ee-AChE was 3-4-times lower than that in solution, one ga ined significantly higher stability. The entrapped enzymes were sensit ive to various organophosphates and to the carbamate carbaryl, with in hibition patterns similar to those obtained in aqueous reactions.