Effect of Calcium Chloride on Choline Esterase

Abstract

THE effect of salts on choline esterase activity has been studied by a number of investigators^1–13. The results may be summarized as follows : (1) True choline esterase : salts with univalent or divalent cations inhibit at low concentrations of acetylcholine, whereas these salts activate at high concentrations of acetylcholine ; the optimum substrate concentration is shifted to higher values, though this was not found by Augustinsson¹⁰. (2) Pseudo-choline esterase : salts with univalent cations inhibit, whereas divalent cations activate. In most experiments, hitherto, acetylcholine only was used as substrate, and choline esterase activities were determined manometrically, thus introducing a possible complicating effect of bicarbonate and other buffers present in the system. An effect of the salts (especially at high concentrations) on the bicarbonate – carbon dioxide equilibrium cannot be excluded.