acetylcholinesterase (AChE) /-kō′lines″tərās/ , an enzyme present at the endings of voluntary nerves and parasympathetic involuntary nerves and autonomic nerve ganglia. It inactivates and prevents the accumulation of the neurotransmitter acetylcholine released during nerve impulse transmission by hydrolyzing the substance to choline and acetate. The action reduces or prevents excessive firing of neurons at neuromuscular junctions.
