ELECTROCHEMICAL APPROACH IN STUDYING THE INACTIVATION OF IMMOBILIZED ACETYLCHOLINESTERASE BY ARSENATE(III)

An acetylcholinesterase amperometric sensor is used to register the cu rrent of oxidation of thiocholine, the product of the acetylcholineste rase atalyzed hydrolysis of acetylthiocholine. The decrease of the val ue of the signal obtained in presence of arsenate(III) is interpreted as due to the diminution of the quantity of the generated thiocholine because of the inhibition of the immobilized acetylcholinesterase on t he surface of a graphite electrode. The experiments were performed var ying the concentrations of the inhibitor and of the substrate, as well as pH. The kinetics of the inactivation of the immobilized acetylchol inesterase by arsenate(III) was investigated. Obtained results could b e employed for the quantitative determinution of AsO33- based on the i nhibition of the immobilized acetylcholinesterase on the surface of a graphite electrode, using an electrochemical approach.