History and New Developments of Assays for Cholinesterase Activity and Inhibition

Biosensors based on ChE inhibition have been developed for monitoring pesticides in food and water samples. AChE hydrolyzes acetylcholine at a higher rate than butyrylcholine but is inhibited by excess substrate. On the other hand, although BChE hydrolyzes butyrylcholine at a higher rate than acetylcholine, it is not inhibited by excess substrate. A ChE inhibitor is known to suppress the activity of the enzyme. AChE inhibitors are traditionally divided into two groups: reversible and irreversible inhibitors. ChE-based assays give a sum parameter of ChE inhibition, and they are not usually capable of discriminating various toxic compounds in a multicomponent sample. Although laboratory testing is generally considered to provide more accurate results, field testing is often an effective alternative since it is faster and less expensive with simpler handling procedures amenable to both mass production and instrument miniaturization.