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 macromethod and a semimicromethod were developed to measure erythrocyte acetylcholinesterase activity in cattle, sheep, goats, horses, dogs, and swine, and to measure plasma cholinesterase activity in horses, dogs, and swine. Comparison of the 2 methods with erythrocytes of sheep, cattle, goats, and horses indicated both methods gave similar results. They can be done in a shorter time and are more sensitive than Michel's method. Normal deltapH values per minutes, with standard deviations for blood cholinesterase activity of animals of different ages, sexes, breeds, and species, were: 0.76 +/- 0.12/30; 0.65 +/- 0.10/15; 0.69 +/- 0.19/45; 0.78 +/- 0.11/45; 0.63 +/- 0.11/45; and 0.71 +/- 0.06/25 for sheep, cattle, goats, horses, dogs, and swine erythrocyte acetylcholinesterase, respectively; and 0.66 +/- 0.18/20; 0.67 +/- 0.20/30, and 0.46 +/- 0.05/60 for horses, dogs, and swine plasma cholinesterase, respectively. It was shown that either the chloride or the iodide salt of acetylcholine can be used as the enzyme substrate. tin blood samples stored at 5 C for 24 hours, there was no significant change of the enzymatic activity.
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PMID:New techniques to measure blood cholinesterase activity in domesticated animals. 1 75

We have identified six molecular forms of acetylcholinesterase (AcChoE: acetylcholine hydrolase, EC 3.1.1.7) in extracts from bovine superior cervical ganglia. We show that three of them resemble the collagen-tailed forms of Electrophorus AcChoE in their hydrodynamic parameters, low-salt aggregation properties, and collagenase sensitivity. The six molecular forms of bovine AcChoE appear structurally homologous to the six forms of electric fish AcChoE that have previously been characterized. They include globular molecules (monomers, dimers, and tetramers) and asymmetric aggregating molecules that possess a collagen-like tail associated with one, two, and three tetramers. We propose to call the globular forms G1, G2, and G4 and the asymmetric forms A4, A8, and A12, the subscripts indicating the number of catalytic subunits. In spite of quantitative differences in their molecular parameters, the AcChoE forms from rat and chicken are clearly homologous to those of bovine AcChoE. Thus the nomenclature we introduce is very probably valid for the main AcChoE molecular forms, at least in vertebrates, and should help to clarify structural relationships and homologies among them. This model, however, does not claim to represent entirely the complex polymorphism of AcChoE, because more or less hydrophobic variants of the G forms have been observed, and because other molecular associations cannot be excluded. We discuss the significance of the globular and collagen-tailed structure for the molecular localization of AcChoE.
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PMID:Asymmetric and globular forms of acetylcholinesterase in mammals and birds. 28 44

Acetylcholinesterase of intact erythrocytes, their ghost and salt soluble extracts obtained from patients with paroxysmal nocturnal haemoglobinuria (PNH) does not differ from normal with respect to Km values for acetylthiocholine, and Ki values for phenyltrimethylammonium iodide. However, the enzyme from PNH sources has lower V max values than normal, has different thermal stability from normal, has less distinctive transition temperature in the Arrhenius plots, and is less subject to inhibition by stearic acid. These results and that from comparison of activation of deoxycholate-extracted enzyme by lipids from normal erythrocytes suggest that the low acetylcholinesterase activity in PNH erythrocytes is due, at least in part, to alteration in the lipid environment of the enzyme.
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PMID:Relation between low erythrocyte acetylcholinesterase activity and membrane lipids in paroxysmal nocturnal haemoglobinuria. 42 42

Acetylcholinesterase was released from bovine erythrocytes in hypo-osmotic sodium phosphate buffer. Initially, about 30% of the enzyme was released in a soluble lipoprotein form, and further incubation resulted in the progressive release of the enzyme in a particulate form. Solubilization of the acetylcholinesterase in the particulate fraction with Lubrol WX (2 mg/ml) resulted in the loss of all lipids except a non-exchangeable fraction identified as cardiolipin. Addition of a mixture of erythrocyte phospholipids to the soluble forms and to the Lubrol WX-solubilized enzyme resulted in the formation of particulate forms of the enzyme with increased partial specific volume and Stokes radius, and a break in the Arrhenius plot of the enzyme activity around 20 degrees C. The break in the Arrhenius plot was abolished by treatment of a soluble enzyme preparation with 1.8 M salt (NaCl) in phosphate buffer, conditions that allowed the extraction of cardiolipin from the enzyme by chloroform/methanol. Failure of the high-salt treatment to decrease the Stokes radius made it unlikely that the bound cardiolipin formed a boundary layer or annulus around the protein. It is suggested that cardiolipin is bound to the core of the dimeric protein structure, thereby controlling the acetylcholinesterase activity.
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PMID:Characterization of lipid-protein interactions in acetylcholinesterase lipoprotein extracted from bovine erythrocytes. 47 49

Lipoprotein forms of acetylcholinesterase from bovine erythrocytes gave non-linear Arrhenius plots with a break at 20 degrees C and contained cardiolipin. The break in the Arrhenius plot was abolished by incubation of the enzyme in high salt (I = 1.8), but only in Ca2+ -chelating conditions. At I = 1.8 neither NaCl alone, CaCl2 nor sodium phosphate at acidic pH abolished the break. However, at this ionic strength either NaCl in 2 mM sodium phosphate (pH 7.4) or sodium phosphate, pH 8, or 1.0 M Na2CO3/NaHCO3 (pH 8.5--10, were able to remove the break. The Arrhenius plot break was regenerated by the addition of Ca2+ to the high salt-treated enzyme with mild homogenization, but could not be regenerated in the presence of EDTA unless CaCl2 was added in excess of the EDTA. Conditions which abolished the break enabled endogenous cardiolipin to be removed from the enzyme by chloroform/methanol extraction Cardiolipin from acetylcholinesterase incubated in high salt in Ca2+ -chelating conditions was not accessible to digestion by phospholipase A2, and was not separated from the enzyme by flotation in a sucrose density gradient or by Sephadex G-200 chromatography. Thus both Ca2+ and cardiolipin appear to be inaccessible, possibly by being tightly associated in the hydrophobic core of the enzyme by ionic and hydrophobic forces. Ca2+ may modulate the temperature dependence of acetylcholinesterase activity through a functionally linked ionic interaction with the enzyme-cardiolipin complex.
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PMID:Involvement of calcium ions in the properties of cardiolipin-associated erythrocyte acetylcholinesterase. 54 28

Several glycolytic enzymes were observed to have between 40-90% of their activities associated with the particulate fractions of lysed nerve endings. The enzymes showing high particulate activity in lysed nerve endings were hexokinase (EC 2.7.1.1), aldolase (EC 4.1.2.13), glucosephosphate isomerase (EC 5.3.1.9), phosphofructokinase (EC 2.7.1.11), glyceraldehyde-phosphate dehydrogenase (EC 1.2.1.12), pyruvate kinase (EC 2.7.1.40) and lactate dehydrogenase (EC 1.1.27). With the exception of phosphofructokinase, 80% or more of the particle associated activity of each enzyme was solubilized by salt treatment indicating the association with particles was ionic. Sub-fractionation of lysed nerve endings showed hexokinase and fumarase (EC 4.2.1.2) had the highest specific activity in the same fractions which is consistent with observations indicating that hexokinase is associated with mitochondria. The other glycolytic zymes having high particulate activity, aldolase, glucosephosphate isomerase, phosphofructokinase, glyceraldehyde-phosphate dehydrogenase, pyruvate kinase and lactate dehydrogenase, showed enrichment in fractions containing synaptosomal membranes, i.e. the fractions having highest specific activity of acetylcholinesterase (EC 3.1.1.7) and (Na+ + K+)-ATPase (EC 3.6.1.3).
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PMID:Association of glycolytic enzymes with particulate fractions from nerve endings. 62 35

The plasma cholinesterase variants of 190 mentally ill individuals having lithium prophylaxis have been examined. A significantly increased frequency of the E1f gene is reported. The effect of lithium nitrate and sodium nitrate on the plasma cholinesterase variants have been shown to be identical in the concentration range 25.0-50.0 mmol/l. The usual enzyme is slightly less sensitive to inhibition by either salt than the dibucaine resistant variant. The evidence suggest that the increased frequency of the E1f gene could be a genetic marker associated with some mental illness and not the result of lithium prophylaxis.
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PMID:Plasma cholinesterase variants in patients having lithium therapy. 85 31

Extraction of membrane proteins from erythrocytes into sonicated phosphatidylcholine vesicles is described. In a process involving phospholipid and neutral lipid exchange, cell membrane proteins associate with the vesicles and can be separated from the cells by centrifugation. The protein transfer appears to be reversible; phospholipid vesicles mediate the delivery of small amounts of previously extracted protein into cell membranes. Prior to extraction, all but one of the proteins are accessible to lactoperoxidase iodination, and lipid analysis indicates that primarily the outer monolayer of the cell is involved in phospholipid exchange. Among the extracted proteins is acetylcholinesterase which is removed much more efficiently by this procedure than by concentrated salt solutions. The most abundant proteins of the erythrocyte membrane are not represented in the vesicle extract.
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PMID:Selective extraction of membrane-bound proteins by phospholipid vesicles. 89 40

A dihydropyridine-pyridine type redox system was successfully applied for delivering a quaternary pyridinium salt, N-methylpyridinium-2-aldoxime chloride (2-PAM), through the blood-brain barrier. The dihydropyridine derivative of 2-PAM was quickly oxidized to 2-PAM after crossing the blood-brain barrier. As a result of this approach, the brain cholinesterase blocked by organophosphates could be reactivated. The new method should be useful in delivering numerous drugs which are otherwise inaccessible to the brain because of their polar ionic character.
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PMID:Delivery of a quaternary pyridinium salt across the blood-brain barrier by its dihydropyridine derivative. 116 5

C57B1/6J, a specific inbred strain of mice with high alcohol preference and DBA/2J, a specific inbred strain with poor preference for alcohol were studied. Brain content of acetylcholine, uptake of 14C-Choline by whole brain homogenate were significantly higher in the C57B1/6J mice whereas brain acetylcholinesterase was higher in the DBA/2J mice. No significant difference was found for the level of brain serotonin, uptake of 3H-norepinephrine or 3H-dopamine. Treatment with a specific inhibitor of choline transferase, 4-(1-napthylvinyl) pyridine salt (10 mg/kg, twice daily) shifted the selection of alcohol to water in the C57B1/6J mice. These findings suggest a direct involvement of central cholinergic mechanism in alcohol preference.
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PMID:Neurochemical correlates of alcohol preference in inbred strains of mice. 122 97


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