Acetylcholine hydrolysis by acetylcholinesterase is inhi-bited at high substrate concentrations. To determine the residues involved in this phenomenon, we have mutated most of the residues lining the active-site gorge but mutating these did not completely eliminate hydrolysis. Thus, we analyzed the effect of a nonhydrolysable sub-strate analogue on substrate hydrolysis and on reactiva-tion of an analogue of the acetylenzyme. Analyses of various models led us to propose the following sequence of events:the substrate initially binds at the rim of the active-site gorge and then slides down to the bottom of the gorge where it is hydrolyzed
