Abstract

The turnover numbers of different acetylcholinesterase forms from electric eel, including the 18 S, 14 S, and 8 S asymmetrical forms and the 11 S lytic form, were measured using an extraordinarily active phosphorylating inhibitor, 7-(diethoxyphosphinyloxy)-N-methylquinolinium ion, as a titrating agent for the concentration of active sites. The 18 S and 14 S forms were about equally active. The 8 S and 11 S forms were about 35% more active than the 18 S and 14 S forms.