cholinesterase

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cholinesterase

 [ko″lin-es´ter-ās]
an enzyme that splits acetylcholine into acetic acid and choline; it occurs primarily in the serum, liver, and pancreas. See also acetylcholinesterase.
true cholinesterase acetylcholinesterase.

cho·lin·es·ter·ase

(kō'lin-es'ter-ās),
One of a family of enzymes capable of catalyzing the hydrolysis of acylcholines and a few other compounds. In mammals, found in white matter of brain, liver, heart, pancreas, and serum. It is also found in cobra venom.
See also: acetylcholinesterase.

cholinesterase

/cho·lin·es·ter·ase/ (-es´ter-ās) serum cholinesterase, pseudocholinesterase; an enzyme that catalyzes the hydrolytic cleavage of the acyl group from various esters of choline and some related compounds; determination of activity is used to test liver function, succinylcholine sensitivity, and whether organophosphate insecticide poisoning has occurred.
true cholinesterase  acetylcholinesterase.

cholinesterase

(kō′lə-nĕs′tə-rās′, -rāz′)
n.
Any of several enzymes that catalyze the hydrolysis of esters of choline, especially acetylcholinesterase.

cholinesterase

[kō′lines′tərās]
an enzyme that acts as a catalyst in the hydrolysis of acetylcholine to choline and acetate. It provides the off mechanism during cholinergic neurotransmission.

cholinesterase

(1) EC 3.1.1.8—synthesized in the liver, present in serum; and
(2) EC 3.1.1.7—acetylcholinesterase, which is synthesised in red cells.

Both enzymes are used to determine the extent of organophosphate exposure; the serum form (EC 3.1.1.8) is more useful in detecting acute toxicity while acetylcholinesterase (EC 3.1.1.7) better reflects chronic exposure.

cholinesterase

There are 2 cholinesterases: one is synthesized in the liver and present in the serum, and the other–now formally known as acetylcholinesterase—is synthesized in the RBCs; both are used to determine the extent of organophosphate exposure; the serum form is more useful in detecting acute toxicity while acetylcholinesterase better reflects chronic exposure; some people have genetic variants of cholinesterase, which act more slowly on substrates than the normal enzyme, and they may experience prolonged apnea after anesthesia with suxamethonium-type muscle relaxants; these variant enzymes can be detected by screening before undergoing anesthesia. See Dibucaine number. Cf Acetylcholinesterase.

cho·lin·es·ter·ase

(ChE) (kō'lin-es'tĕr-ās)
One of a family of enzymes capable of catalyzing the hydrolysis of acylcholines and a few other compounds. Found in cobra venom.

cholinesterase

An enzyme that rapidly breaks down acetylcholine to acetic acid and choline so that its action as a NEUROTRANSMITTER ceases.

cholinesterase

an enzyme that hydrolyses and destroys excess ACETYLCHOLINE after it has been liberated and has produced its effect on specific sites on the postsynaptic membrane at a nerve synapse. See NERVE IMPULSE.

cho·lin·es·ter·ase

(kō'lin-es'tĕr-ās)
One of a family of enzymes capable of catalyzing the hydrolysis of acylcholines and a few other compounds. In mammals, found in white matter of brain, liver, heart, pancreas, and serum.

cholinesterase (kō´lines´tərās),

n an esterase that hydrolyzes acetylcholine. It is an enzyme that is widely distributed throughout the muscles, glands, and nerves of the body and that converts acetylcholine into choline and acetic acid.

cholinesterase

an enzyme that splits acetylcholine into acetic acid and choline. Called also acetylcholinesterase.
This enzyme is present throughout the body, but is particularly important at the neuromuscular junction, where the nerve fibers terminate. Acetylcholine is released when a nerve impulse reaches a neuromuscular junction. It diffuses across the synaptic cleft and binds to cholinergic receptors on the muscle fibers, causing them to contract. Cholinesterase splits acetylcholine into its components, thus stopping stimulation of the muscle fibers. The end products of the metabolism of acetylcholine are taken up by nerve fibers and resynthesized into acetylcholine.

cholinesterase inhibitor
the drugs neostigmine, physostigmine and pyridostigmine inhibit cholinesterase. These drugs are used to treat myasthenia gravis, a disease in which the cholinergic receptors are attacked by autoantibodies. The drugs extend the effect of acetylcholine on the muscle fiber.
cholinesterase reactivator
choline-reactivating oximes are effective antidotes in organophosphorus insecticide poisoning, a state of acetylcholine excess because of cholinesterase inhibition. 2-PAM (2-pyridine aldoxime methchloride) is the most popular oxime for this purpose.