acetylcholinesterase

(ə-sēt'l-kō'lə-nĕs'tə-rās', -rāz')
n.
Any of various enzymes in the blood and in certain tissues that catalyze the hydrolysis of acetylcholine.

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An enzyme that breaks down acetylcholine (ACh) into choline and acetic acid. Acetylcholinesterase is released onto the sarcolemma of muscle fibres and destroys ACh after the ACh has combined with receptors on the muscle fibre. Thus, acetylcholinesterase prevents continued muscle contraction in the absence of additional nervous stimulation.

(ə-sēt'l-kō'lə-nĕs'tə-rās', -rāz')
n.

Any of various enzymes in the blood and in certain tissues that catalyze the hydrolysis of acetylcholine.

abbr.: AChE; EC 3.1.1.7; systematic name: acetylcholine acetylhydrolase; other names: true cholinesterase; cholinesterase I; an esterase enzyme that catalyses the hydrolysis of acetylcholine to choline and acetate; it also acts on a variety of acetic esters and catalyses transacetylations. It is found in or attached to cellular or basement membranes of presynaptic cholinergic neurons and postsynaptic cholinoceptive cells. A soluble form occurs in cerebrospinal fluid and within cholinergic neurons. It is inhibited by a number of drugs, e.g. physostigmine, and by several organophosphates. The 3-D structure is known for fragments obtained from the electric ray(fish).

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An enzyme present in nervous tissue, muscle and red cells that catalyzes the hydrolysis of acetylcholine to choline and acetic acid; called also true cholinesterase. Abbreviated AChE.

• a. antagonists — organophosphorus compounds and carbamates that act by inactivating acetylcholinesterase; hence poisoning by these compounds has parasympatheticomimetic manifestations.