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cholinesteraseenUK
cho·li·nes·ter·ase C0321200 (kō′lə-nĕs′tə-rās′, -rāz′)n. Any of several enzymes that catalyze the hydrolysis of esters of choline, especially acetylcholinesterase. [cholin(e) + esterase.]cholinesterase (ˌkəʊlɪˈnɛstəˌreɪs; ˌkɒl-) n (Biochemistry) an enzyme that hydrolyses acetylcholine to choline and acetic acidcho•lin•es•ter•ase (ˌkoʊ ləˈnɛs təˌreɪs, -ˌreɪz, ˌkɒl ə-) n. an enzyme, found esp. in the heart, brain, and blood, that hydrolyzes acetylcholine to acetic acid and choline. [1930–35] ThesaurusNoun | 1. | cholinesterase - an enzyme that hydrolyses acetylcholine (into choline and acetic acid)enzyme - any of several complex proteins that are produced by cells and act as catalysts in specific biochemical reactions | TranslationsCholinesteraseenUK
cholinesterase[′kō·lə′nes·tə‚rās] (biochemistry) An enzyme found in blood and in various other tissues that catalyzes hydrolysis of choline esters, including acetylcholine. Abbreviated chE. Cholinesterase any of a group of enzymes of the hydrolase class that act as a catalyst in the hydrolysis of choline esters, according to the equation (CH3)3N + CH2CH2OCOR + H2O → (CH3)3N+ CH2CH2OH + RCOOH The cholinesterase of the greatest biological importance is that of the nervous system, acetylcholinesterase (ACE), which acts as a catalyst mainly for the hydrolysis of acetylcholine (R = CH3). Cholinesterases that hydrolyze predominately the esters of choline and other carboxylic acids, such as propionic and butyric acid, have retained the trivial name cholinesterase. ACE catalyzes the hydrolysis of acetylcholine to acetic acid and choline. Acetylcholine, a highly active substance, is secreted in the synapses of the nervous system and takes part in the transmission of nerve impulses from one nerve cell to the next and from nerve cells to the appropriate organs, such as muscles and endocrine glands. It must be rapidly broken down, however, because accumulations of it block the transmission of nerve impulses and cause paralysis—that is, the loss of nerve functions. For this reason, substances that suppress ACE activity are highly toxic; such substances include organophosphate insecticides, physostigmine, and proserine. An enzyme with properties similar to those of ACE is found in erythrocytes, but its biological function is not yet known. Less specific cholinesterases are found in blood serum and certain organs and tissues of animals. The most active ACE has been discovered in the electric organs of fish of the suborder Batoidea. Individual cholinesterases of high purity have been obtained from various organs and tissues. All cholinesterases are proteins with molecular weights ranging from 70,000 to 1,000,000; they contain no coenzymes of low molecular weight. A very important role in the catalytic activity of cholinesterases is played by the amino acids serine, histidine, aspartic acid, and glutamic acid. V. A. IAKOVLEV cholinesteraseenUK
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" >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. Synonym(s): choline esterase II, nonspecific cholinesterasecholinesterase (kō′lə-nĕs′tə-rās′, -rāz′)n. Any of several enzymes that catalyze the hydrolysis of esters of choline, especially acetylcholinesterase.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. See CHE See CHEcholinesteraseenUK Related to cholinesterase: acetylcholine, cholinesterase test, Cholinesterase enzyme, Cholinesterase inhibitorsWords related to cholinesterasenoun an enzyme that hydrolyses acetylcholine (into choline and acetic acid)Related Words |