Effect of organic solvents on acetylcholinesterase inhibition and enzyme kinetics.

Abstract

The most widespread signalling system in the brain is the cholinergic system, which plays a central role in the progress of Alzheimer's diseases (AD). Current AD treatment primarily targets the neuronal acetylcholinesterase (AChE) enzyme. The finding of AChE activity may play a vital role in optimizing assays for drug discovery of new AChE inhibiting agents. During in-vitro assay of AChE activity, the use of various organic solvents is imperative. Therefore, evaluating the effect of different organic solvents on enzyme activity and enzyme kinetics is essential. Organic solvents' AChE inhibitory potential (including enzyme kinetics: Vmax, Km and Kcat) was evaluated using a substrate velocity curve by using the non-linear reversion Michaelis-Menten kinetic function. DMSO was found to have the most potent AChE inhibitory effect, followed by acetonitrile and ethanol. The kinetic study revealed DMSO as a mixed inhibitory effect (competitive/non-competitive manner), ethanol as non-competitive, and acetonitrile as a competitive inhibitor of the AChE enzyme. Methanol has shown a negligible impact on enzyme inhibition and kinetics, suggesting its suitability for the AChE assay. We assume that our study results will help design the experimental protocols and support analyzing investigational outcomes while screening and biological evaluation of new molecules using methanol as solvent/cosolvent.