Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:3.1.1.7 (acetylcholinesterase)
28,390 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A screening aimed at obtaining a cholinesterase inhibitor of microbial origin was carried out using Pseudomonas butyrylcholinesterase. A mycelium-extract of a fungus strain, belonging to the genus Penicillium, was found to produce such an enzyme inhibitor. The inhibitor was purified and crystallized as colorless leaflets. From physical and chemical studies, the inhibitor was identified as being identical with an antibiotic, mycelianamide, though this compound was not known to have enzyme inhibitor activity. The kinetics of the inhibition of Pseudomonas butyrylcholinesterase were also studied. Horse serum cholinesterase and hog liver carboxylesterase were also inhibited by the isolated Penicillium C-81 inhibitor, but lipase and acetylcholinesterase were not.
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PMID:A butyrylcholinesterase inhibitor produced by Penicillium sp. no. C-81 and its identity with mycelianamide. 95 41

Octadecyl-bonded silica, commonly used for reverse-phase high-pressure liquid chromatography, was modified using surfactants bearing ionizable groups and the modified packing used in ion-exchange chromatography of proteins. The surfactants 2-(n-hexadecylheptaethoxy)acetic acid, 1-(n-hexadecyloctaethoxy)ethylene-diamine, and N-(n-hexadecyloctaethoxy)pyridinium were adsorbed onto test columns packed with octadecyl-bonded silica particles. The proteins lysozyme, bovine serum albumin, trypsin, horse serum cholinesterase, and bovine liver carboxylesterase were used to study the ion-exchange characteristics of the modified packings. The retention order of the proteins on the surfactant-modified stationary phases were as predicted by the isoelectric point of each protein. In addition, the interaction of enzymes with the packings did not result in significant loss of enzymatic activity. Surfactant removal was possible with the use of organic solvents and this allowed the octadecyl-bonded surface to be used again in the reverse-phase mode. During the course of the experiments, no degradation in the packing's performance was observed due to loss of adsorbed surfactant, even after over 85,000 column volumes of sodium chloride and Tris-HCl buffers were circulated through the column.
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PMID:Reversible conversion of octadecyl-bonded silica to ion-exchange surfaces for protein separations. 254 Jun 75

Initially, mice were pretreated with atropine (17.4 mg/kg; IP) and the oxime reactivator HI-6 (50 mg/kg; IP) 5 min prior to an injection of soman (287 micrograms/kg, SC); approximately 2.1 x LD50 dose). More than 95% of the mice survived this dose of soman with atropine and HI-6 pretreatment. In these survivors of soman poisoning the return of the soman LD50 value to control value (124 micrograms/kg, SC) was determined at various times after the initial soman exposure. Mice which survived exposure to a lethal dose of soman by pretreatment with atropine and HI-6 were sensitized to the lethal effects of soman upon reexposure. The SC soman LD50 at 4 h, after surviving the initial soman exposure, was 20 micrograms/kg. The normal soman LD50 (as evidenced by a LD50 value which was not significantly different from the control value) returned within 4 days, at which time there was still extensive acetylcholinesterase inhibition in all brain regions (striatum, pons-medulla, cerebellum, hypothalamus, hippocampus), diaphragm and erythrocytes. Serum carboxylesterase recovered to control levels within 48 h, whereas liver carboxylesterase activity was not inhibited following the initial soman exposure. The results demonstrate that there is an excess of acetylcholinesterase which is required for normal response in the toxicological sense.
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PMID:Survivors of soman poisoning: recovery of the soman LD50 to control value in the presence of extensive acetylcholinesterase inhibition. 273 Mar 40

A method is described for the routine determination of the rate of colorimetric enzyme reactions using a 96-well microtiter plate reader commonly used in immunoassay. This approach is illustrated by monitoring esterase activity using three common products: release of thiol, release of ethanol, and release of p-nitrophenylate ion. Examples include monitorings of the rate of hydrolysis of acetylthiocholine iodide by eel acetylcholinesterase and the rate of hydrolysis of malathion and nonconventional esters such as O-methyl, O-ethyl, and O-isobutyl carbonates of p-nitrophenol by commercial porcine liver carboxylesterase. Data obtained from the plate reader were compared to those obtained, under similar conditions, in a conventional spectrophotometer. Absorbance measurements made in both machines on the same solution, as well as absorbance changes measured over time, were similar. The use of the 96-well plate format tremendously increased the number of enzyme assays carried out per person and the interface with a personal computer allowed rapid manipulation of the absorbance values to calculate the desired rate data. This approach should be generally applicable to many routine colorimetric assays in the research laboratory.
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PMID:Use of a 96-well microplate reader for measuring routine enzyme activities. 343 78

The interaction of dialkyl (alpha-carbometoxy-beta,beta,beta-trifluoroethyl) phosphates (RO)2P(O) . OCH(CF3)COOMe (R = Me, Et, Pr, Pri, Bu, Bui, Am, Hex) (I-VIII) with human erythrocyte acetylcholinesterase, horse serum butyrylcholinesterase, pig liver carboxylesterase was studied and acute toxicity in mice was estimated. Compounds (I)-(VIII) were not hydrolyzed by carboxylesterase, slowly and irreversibly inhibited acetylcholinesterase (kII = 10(2)-10(4) M-1 X min-1) and more efficiently inhibited butyrylcholinesterase and carboxylesterase (kII = 10(3)-10(7) M-1 X min-1). The structure--antienzymatic activity relationships were investigated. With increasing of hydrophobicity of alkoxy groups, antienzymatic activity to butyrylcholinesterase and carboxylesterase ("sites of loss") rises equally and more significantly, than antiacetylcholinesterase activity (delta lg kII 1.0 and 2.4 for R = CH3 and C5H11 resp.). Branching at the alpha-position of alkoxy groups leads to sharp reducing of acetylcholinesterase and butyrylcholinesterase inhibition constants, the carboxylesterase inhibition mechanism becoming reversible. Multiple regression analysis (the Kubinyi model) showed that influence of steric hindrances is revealed at the phosphorylation stage. It was found that phosphates (I)-(VIII) possess low acute toxicity in mice (900-2000 mg/kg). The toxicity of this homologous series appears to be independent of the hydrophobicity. Role of esterases in toxicological effect of compounds (I)-(VIII) is discussed.
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PMID:[Interaction of dialkyl(alpha-carbomethoxy-beta,beta,beta-trifluoro- ethyl) phosphates with mammalian esterases]. 356 18

The pretreatment of calves with a single dose of 10 mg kg-1 dieldrin or 21 daily doses of 10 mg kg-1 phenobarbitone increased the toxicity of diazinon as reflected by the development of more severe clinical signs and greater depression in whole blood cholinesterase activity in the pretreated calves. Induction by dieldrin or phenobarbitone of the hepatic microsomal enzyme amidopyrine-N-demethylase was also accompanied by a concurrent rise in the liver carboxylesterase activity.
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PMID:Effect of pretreatment with hepatic microsomal enzyme inducers on the toxicity of diazinon in calves. 380 24

Tri-ortho-tolyl phosphate (TOTP), 360 mg/kg, po, and 0,0'-diisopropyl phosphorofluoridate (DFP), 1 mg/kg sc, were administered to adult White Leghorn chickens 24 hr after they were placed on diets containing 0 to 300 ppm corticosterone. Supplemented diets were continued until clinical signs and lesions of delayed neuropathy appeared. Although low concentrations (less than or equal to 50 ppm) of corticosterone had beneficial effects on TOTP-induced neuropathy, greater than or equal to 200 ppm exacerbated clinical signs in chickens given either TOTP or DFP. Neurotoxic esterase activities 24 hr after TOTP or DFP were less than 20% of values measured in chickens not given organophosphorous compounds. Chickens given 200 ppm corticosterone without TOTP or DFP had significantly elevated activity of plasma cholinesterase and significantly inhibited activity of liver carboxylesterase. Degenerating myelinated fibers were also evident in distal levels of the peripheral nerves of chickens given TOTP or DFP.
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PMID:Dose-related beneficial and adverse effects of dietary corticosterone on organophosphorus-induced delayed neuropathy in chickens. 396 13

Interaction of insectoacaricide Me (EtO)P(S)SCH2SCH2COOMe (I), its activation metabolites (P = O (II), S = O, and P = O, S = O (III) analogues), and a detoxication product (-COOH analoque (IV) with rat liver carboxylesterase, acetylcholinesterase and butyrylcholinesterase of warm-blooded animals, as well as with cholinesterase and carboxylesterase of American cockroach has been studied. Low toxicity of (I) towards warm-blooded animals and American cockroach is shown to result from its rapid hydrolysis with corresponding carboxylesterases to form (IV). Monothiophosphonates (II) and (III) are not hydrolyzed by carboxylesterases but inhibit them irreversibly. High toxicity of (I) towards aphids can be ascribed to low activity of the carboxylesterase of that insect.
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PMID:[The role of esterases in the toxicity of organothiophosphorus insectoacaricides containing a fragment of mercaptoacetic acid]. 405 20

Carboxylesterase was obtained from human liver in an electrophoretically homogeneous form. The monomeric molecular weight of the enzyme was 60,000 and the enzyme associated to form trimers. Purified human liver carboxylesterase was compared with human serum carboxylesterase, purified earlier. Serum carboxylesterase hydrolyzed a typical cholinesterase substrate and aryl acylamide, whereas liver carboxylesterase did not hydrolyze these compounds. Both carboxylesterases catalyzed the hydrolysis of short-chain triacylglycerols, such as tributyrin, and medium-chain monoacylglycerols, such as monocaprin, but not the hydrolysis of long-chain triacylglycerols. Serum carboxylesterase activity was inhibited by p-trimethylammoniumanilinium dichloride and neostigmine, whereas liver carboxylesterase activity was not affected by these compounds. Liver and serum carboxylesterase activities were both strongly inhibited by phenylmethylsulfonyl fluoride.
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PMID:Human liver carboxylesterase. Properties and comparison with human serum carboxylesterase. 641 19

The interaction of human erythrocyte acetylcholinesterase, horse serum butyrylcholinesterase and rat liver carboxylesterase with insecticides (RO)2P(O)SCH(COOEt)SP(O)(OR)2 (I) and (RO)2P(O)SCH(COOEt)OP(S)(OR)2 (II) was studied. The type I and II compounds were not hydrolyzed by carboxylesterase and inhibited the esterases irreversibly. A complex pattern of inhibition of acetylcholinesterase and butyrylcholinesterase by these compounds was caused by kinetically-manifested formation of an enzyme-inhibitor complex. The compounds I and II were more selective towards butyrylcholinesterase than towards acetylcholinesterase and carboxylesterase (kII two orders of magnitude higher) because of effective binding in the butyrylcholinesterase active center (K alpha 10(-8)--10(-9) M) due to hydrophobic interaction. An important role of the thion-phosphoryl-containing fragment in the interaction of type II compounds with hydrophobic sites of butyrylcholinesterase and carboxylesterase active centers was established.
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PMID:[Interaction of bis-phosphorylated methanes with mammalian esterases]. 651 64


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