Electrochemical Study on the Kinetic Behavior of the Immobilized Acetylcholinesterase

In this work are reported new results on the type of the immobilized acetylcholinesterase inhibition by specific and non-specific inhibitors, as well as the values of the characteristic enzyme reaction kinetic parameters in the absence and in the presence of inhibitors, identified applying an electrochemical approach. It was found that: -The kinetics of the process of acetylthiocholine hydrolysis catalyzed by the immobilized acetylcholinesterase is complicated by mass transfer constraints, at low substrate concentrations; -The inhibition of the immobilized acetylcholinesterase by specific inhibitors (trichlorfon, oxophosphol, galantamine, caffeine, atropine, nicotinic acid, and eserine) is of a competitive type, while quinine and thiamine acts as non-competitive inhibitors; -The character of acetylcholinesterase inhibition in heterogeneous phase by non-specific inhibitors (Hg2+, Cu2+, Cd2+, Mn2+, Fe3+, and AsO33-) is reversible and non-competitive. The reactivity of the inhibitors decreases in the order: Hg2+ → Cu2+ → Cd2+ → AsO33- → Fe3+ → Mn2+.