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:3.1.1.8 (cholinesterase)
12,691 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Species differences in the hydrolysis of isocarbacyclin methyl ester (TEI-9090) in whole blood and in its separated components were studied in rats, dogs and human. Esterase activity in rat whole blood was approximately 100 and 400 times higher than that in dog and human whole blood, respectively, and was attributed to high plasma activity. In contrast, TEI-9090 hydrolysis activities in dog and human blood were due to red blood cells (RBC), whose activity in humans was slightly suppressed by albumin. In dogs, activity in RBC membranes was 10 times greater than in the cytosol, while in human membrane and cytosol activity was virtually the same. The effects of the esterase inhibitor diisopropylfluorophosphate, bis-p-nitrophenylphosphate (BNPP), eserine, 5,5'-dithiobis-(2-nitrobenzoic acid) (DTNB) and p-chloromercuribenzoate showed that the rat plasma and RBC cytosol esterases hydrolysing TEI-9090 were carboxylesterase (CarbE) and arylesterase (ArE), respectively. The esterases in dog plasma and RBC membrane were CarbE, and RBC cytosol esterase was ArE. In humans, the esterase activities in plasma, RBC membrane and cytosol were butyrylcholinesterase, CarbE and ArE, respectively.
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PMID:Species differences in hydrolysis of isocarbacyclin methyl ester (TEI-9090) by blood esterases. 776 77

A large cDNA fragment covering the complete sequence of the mature catalytic subunit of rabbit acetylcholinesterase (AChE) has been cloned and sequenced. This sequence was compared to that of rabbit butyrylcholinesterase [BChE; Jbilo, O. & Chatonnet, A. (1990) Nucleic Acids Res. 18, 3990]. Amino acid sequences of AChE and BChE have 51% identity. They both possessed a choline-binding site W84, a catalytic triad S200-H440-E327 and six cysteine residues (positions 67-94, 254-265, 402-521) in conserved sequence positions to those that form three intrachain disulfide bonds in all cholinesterases (by convention, numbering of amino acids is that used for Torpedo AChE). Rabbit AChE had a larger number of aromatic residues lining the active-site gorge than rabbit BChE (14 compared to 8, respectively) and a smaller number of potential N-glycosylation sites (3 compared to 8, respectively). Both catalytic subunits have a hydrophilic C-terminus (catalytic subunits of type T). Expression of acetylcholinesterase and butyrylcholinesterase genes (ACHE and BCHE) was studied in rabbit tissues and during development by a correlation of Northern-blot analysis and enzymic activities. This correlation was rendered difficult by the presence of an eserine-resistant esterase active on butyrylthiocholine in serum, liver and lung. When the contribution of this carboxylesterase was taken into account, brain was found as the richest source of BChE followed by lung and heart. Rabbit liver had a very low content of BChE that correlated with the low BChE activity in plasma. During development, BCHE transcripts were detected as early as day 10 post coitum, whereas ACHE transcripts appeared only on day 12.
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PMID:Acetylcholinesterase and butyrylcholinesterase expression in adult rabbit tissues and during development. 792 28

The effect of long-term exposure to the organophosphate insecticide Anthio on serum esterases and ruminal microorganisms of male calves was investigated. The daily oral administration of 3, 6 or 12 mg Anthio/kg/d for 90 d caused significant inhibition of serum cholinesterase (10-28%) and carboxylesterase (12-33%) in male calves. Toxic signs characteristic of anticholinesterase poisoning were observed during 25-70 d of exposure to 6 and 12 mg Anthio/kg. The dose of 12 mg Anthio/kg was lethal to 1/5 calves. Total protozoal population was decreased significantly (15-27%) following 6 and 12 mg Anthio/kg, whereas reduction in total bacterial population (18%) was only significant at 12 mg Anthio/kg.
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PMID:The effect of long-term exposure to anthio on serum esterases and ruminal microorganisms of male calves. 806 63

Esterases in human liver microsomes hydrolysed fluazifop-butyl (Vmax 9.8 +/- 1.6 mumol/min/g tissue), paraoxon (Vmax 47.4 +/- 7.5 nmol/min/g tissue) and phenylacetate (Vmax 57 +/- 8 mumol/min/g tissue), whereas esterases found in the human liver cytosol hydrolysed fluazifop-butyl (Vmax 10.0 +/- 0.5 mumol/min/g tissue) and phenylacetate (Vmax 37 +/- 2.9 mumol/min/g tissue) but not paraoxon. Human plasma esterase hydrolysed fluazifop-butyl (Vmax 0.09 +/- 0.006 mumol/min/mL), paraoxon (Vmax 210 +/- 14 nmol/min/mL) and phenylacetate (Vmax 250 +/- 17 mumol/min/mL). Inhibitory studies using paraoxon, bis-nitrophenol phosphate and mercuric chloride indicated fluazifop-butyl hydrolysis involved carboxylesterase in liver microsomes and cytosol, and cholinesterase and carboxylesterase in plasma. Phenylacetate hydrolysis involved arylesterase in plasma, both arylesterase and carboxylesterase in liver microsomes and carboxylesterase in liver cytosol. Plasma hydrolysis is less important and overall esterase activity is lower in humans than in the rat which is therefore a poor model.
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PMID:Human xenobiotic metabolizing esterases in liver and blood. 821 61

The chlorofluorocarbon substitute 1,2-dichloro-1,1-difluoroethane (HCFC-132b) undergoes oxidative metabolism in rats to give a range of metabolites, including chlorodifluoroacetaldehyde [Harris and Anders (1991) Chem. Res. Toxicol. 4, 180]. The present experiments were undertaken after studies to characterize an unidentified metabolite of HCFC-132b revealed that chlorodifluoroacetaldehyde was toxic in vivo: rats given chlorodifluoroacetaldehyde died showing signs of cholinergic stimulation. Because some fluoroketones are known inhibitors of hydrolases, including acetylcholinesterase, the inhibitory effects of chlorodifluoroacetaldehyde on acetylcholinesterase (electric eel and human erythrocyte), on pseudocholinesterase (horse serum), on carboxylesterase (pig liver), and on alpha-chymotrypsin (bovine pancreas) were studied. In aqueous solution, the ratio chlorodifluoroacetaldehyde:chlorodifluroacetaldehyde hydrate, as determined by 1H nuclear magnetic resonance spectroscopy, was 1:157. Chlorodifluoroacetaldehyde was a slow-binding inhibitor of both acetylcholinesterases, of pseudocholinesterase, and of carboxylesterase; the Ki values, corrected for the aldehyde:hydrate ratio, were 150 nM, 1.7 nM, 3.7 nM, and 23 pM, respectively, as determined by final velocity of the progress curves; the kon values were 9.1 x 10(4), 1.1 x 10(5), 3.2 x 10(4), and 9.2 x 10(5) M-1 min-1, respectively. Chlorodifluoroacetaldehyde did not inhibit alpha-chymotrypsin. Acetaldehyde and trichloroacetaldehyde were classical competitive inhibitors of acetylcholinesterase. These results show that hydrochlorofluorocarbon metabolites may exert significant biological effects.
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PMID:Slow-binding inhibition of carboxylesterase and other serine hydrolases by chlorodifluoroacetaldehyde. 829 40

The question addressed is whether an increased intake of cholesterol affects esterase-1 (EC 3.1.1.1; ES-1) and butyrylcholinesterase (EC 3.1.1.8) activity in plasma. Rats were fed on a purified diet either without or with cholesterol (10 g/kg) added at the expense of the carbohydrate source. Dietary cholesterol significantly decreased plasma butyrylcholinesterase activity, but raised plasma ES-1 activity. Evidence is discussed, suggesting that plasma butyrylcholinesterase is involved in plasma cholesterol metabolism, whereas esterase-1 is involved in intestinal cholesterol absorption.
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PMID:Dietary cholesterol lowers the activity of butyrylcholinesterase (EC 3.1.1.8), but elevates that of esterase-1 (EC 3.1.1.1) in plasma of rats. 829 10

The kinetics of time- and concentration-dependent covalent organophosphorus inhibition of carboxylesterase isoenzymes (EC 3.1.1.1) and cholinesterase isoenzymes (EC 3.1.1.7 and EC 3.1.1.8) were investigated using a wide range of organophosphate inhibitor concentrations (10(-10)-10(-3) mol/l) and different inhibition times. Computerized analysis of inhibition curves by weighted non-linear least-squares curve fitting was compared to graphic analysis by iterative elimination of exponential functions. Possible experimental errors due to inhibitor saturation kinetics and enzymatic organophosphate hydrolysis were thoroughly investigated. In mammalian heart muscle, three different cholinesterase isoenzymes were identified. High sensitivity and specificity of the classic differential inhibition test for carboxylesterase activity of hen brain neuropathy target esterase (NTE) could be confirmed independently with both methods of inhibition curve analysis.
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PMID:Computerized analysis of covalent inhibition kinetics for identification of heart muscle cholinesterase and brain carboxylesterase isoenzymes. Design of differential inhibition assays. 834 80

The influence of genotypes of the major histocompatibility complex (MHC) on susceptibility to acute and delayed effects of an organophosphorus ester was measured in adult White Leghorn chickens from lines differing in response to sheep red blood cell (SRBC) antigen. Chickens from lines selected for high (HA) or low (LA) antibody response to SRBC and homozygous for B13B13 or B21B21 genotypes at the MHC were administered a single subcutaneous injection of diisopropyl phosphorofluoridate (DFP) at dosages of 0, 0.25, 0.50, or 1.0 mg/kg body weight using corn oil as the carrier. Criteria for toxicological responses included clinical, biochemical, and pathological measures. Clinical signs of acute cholinergic poisoning and delayed neuropathy were dose related. Brain and blood cholinesterase and carboxylesterase activities were more sensitive to inhibition by DFP than were liver cholinesterase and carboxylesterase activities. Cholinergic signs 3 h after administration of DFP were more pronounced in line HA than in line LA chickens. Pathological evidence of delayed neuropathy 2 wk after DFP administration was also more evident in HA than LA chickens. Although less pronounced than that for lines, differences in neurotoxic manifestations following DFP administration were greater for chickens of B21B21 than B13B13 genotypes. Activity of A-esterases, which hydrolyze organophosphorus esters without being inhibited by them, was lower in plasma of line HA than line LA chickens. Differences among the genotypes in activity of other esterases were not found in chickens not receiving DFP. These results indicated that responses of chickens to the neurotoxicant DFP were influenced by the background genome of the chickens.
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PMID:Differences between genetic stocks of chickens in response to acute and delayed effects of an organophosphorus compound. 834 37

The ability of a selected strain of the malaria vector Anopheles gambiae to encapsulate the early oocysts of the malaria parasite Plasmodium cynomolgi B has previously been shown to be genetically linked to specific esterase phenotypes. This association between Plasmodium susceptibility and esterase phenotype is found in the An. gambiae G3 strain from which the Plasmodium-refractory and -susceptible mosquito strains were derived. Genetic crosses had suggested that the esterase phenotypes reflect the assortment of two alleles at one esterase genetic locus, with the two esterase homozygotes showing Plasmodium-susceptible and -refractory phenotypes and the esterase heterozygote being intermediate in susceptibility. By using a variety of specific esterase inhibitors in conjunction with esterase staining of gel-electrophoresed mosquito homogenates, we found that the bands previously thought to reflect one genetic locus are actually the product of two different esterase loci, Est1, a cholinesterase, and Est2, a carboxylesterase. In addition, examination of chromosomal inversions and the esterase phenotype in the An. gambiae G3 strain revealed that different forms of a polymorphic inversion on the left arm of chromosome two (the 2La inversion) are inseparably associated with different alleles at these two esterase loci. We conclude that the genetic association among the esterase-linked Plasmodium-susceptibility locus and the two esterase loci is maintained by the suppression of recombination in 2La inversion heterozygotes in the An. gambiae G3 strain and its selected derivatives.
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PMID:Association of two esterase genes, a chromosomal inversion, and susceptibility to Plasmodium cynomolgi in the African malaria vector Anopheles gambiae. 837 56

A cDNA encoding human liver carboxylesterase and its gene were isolated. Nucleotide sequence analyses of the cDNA revealed that the predicted enzyme protein consists of 567 amino acids, including 18 amino acids of a putative signal peptide. Comparison of the deduced amino acid sequences of this enzyme with those of seven other carboxylesterases in various mammalian species, together with experimental data from several other laboratories, showed that these enzymes can be classified into three groups depending on the sequences at their carboxyl terminals and the presence or absence of one exon. A human carboxylesterase gene was found to span approximately 30 kb and to have 14 small exons. Alignments of this gene with those of human cholinesterase and rat cholesterol esterase indicated insertional sites at some introns and homologous amino acid sequences around them, although these genes have different numbers of exons. Thus the results supported the conclusion that these esterases evolved from a common ancestral gene.
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PMID:Molecular cloning and characterization of a human carboxylesterase gene. 840 73


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