cholinesterase

an enzyme that breaks down a choline ester into its choline and acid components. The term usually refers to acetylcholinesterase, which breaks down the neurotransmitter acetylcholine into choline and acetic acid. It is found in all cholinergic nerve junctions, where it rapidly destroys the acetylcholine released during the transmission of a nerve impulse so that subsequent impulses may pass. Other cholinesterases are found in the blood and other tissues.