Enthalpimetric measurements of the strengths of immobilized cholinesterase inhibitors

A rapid, reproducible method is described for the enthalpimetric determination of the relative inhibitory strengths of a series of 29 reversible acetylcholinesterase and butyrylcholinesterase inhibitors. The technique continuously monitors the activity of glass-immobilized cholinesterases, which can be rapidly and quantitatively reactivated simply by removal of the inhibitor. Complete inhibition curves are presented for some of the most potent inhibitors. For the strongest inhibitors, it is possible to detect amounts as low 5×10−9 mol.