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 decrease in total activity of ATPase and in specific activity of Na+,K+-ATPase as well as less rapid and distinct decrease in specific activity of acetylcholinesterase were observed in synaptosomal membrane after binding of bilirubin in vitro. Irradiation with blue light of the bilirubin-containing membrane particles caused a more distinct decrease in activity of these enzymes. Blood serum albumin, added to the suspension of bilirubin-containing particles of synaptosomal membrane, affected significantly the alterations in activity of membrane-bound enzymes caused by the irradiation. Character of the effect depended on pH of the medium and presence of organophilic ligands in blood serum albumin molecule.
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PMID:[Functional changes in the synaptic membrane during in vitro interaction with bilirubin and serum albumin]. 256 Aug 69

Samples of left hippocampus, septal nucleus, parietal lobe (area 40), and nucleus basalis of Meynert (NBM) were removed from eight patients with pathologically confirmed Alzheimer's disease (AD), four controls, and three patients with non-Alzheimer's dementia. Extracts of these brain regions were assayed for choline acetyltransferase (ChAT) specific activity, acetylcholinesterase (AChE) specific activity, and AChE molecular form composition. Average specific activities of ChAT from hippocampus, septum, and area 40, but not NBM, were significantly lower (p less than 0.01) in the AD population than in the control group. The average AChE specific activity was significantly less (p less than 0.05) in hippocampus and area 40 when the AD group was compared with controls. The average percentage of total AChE activity represented by the globular tetrameric (G4) molecular form was decreased in all AD brain regions as compared to control or to non-Alzheimer's demented groups. The decrease in G4 was, in all cases, due to a selective decrease in the membrane-bound form of G4. The loss of percent membrane-bound G4 in the AD group was significant for hippocampus (p less than 0.05) and area 40 (p less than 0.001) when compared to controls. The percentages of total AChE present as G4 and as membrane-bound G4 in each brain region were correlated with the ChAT specific activities in that region. The correlations showed that AChE molecular form composition changed significantly only if ChAT activity fell below a certain consistent level. The human data agreed well with data from fornix-lesioned mice which strongly suggest the existence of a soluble factor that regulates production of membrane-bound G4.
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PMID:Decrease in membrane-bound G4 form of acetylcholinesterase in postmortem Alzheimer brain. 260 28

Using selective inhibitor treatments, we have studied the distribution of asymmetric (A) and globular (G) forms of acetylcholinesterase (AChE) in the extra- and intracellular compartments of chick retina, a specialized region of chick central nervous system (CNS). Our results show that the chick retinal collagen-tailed AChE (an example of class II asymmetric molecular forms) is essentially an extracellular form of the enzyme; this is the first demonstration of the extracellular localization of asymmetric AChE in the vertebrate CNS. The active site of most of the hydrophobic, membrane-bound G4-form is also exposed to the external environment. In turn, the smaller molecular weight G-forms (G2 and G1) are localized within the cells, where they may represent intermediate components in the assembly or degradation of the more complex enzymatic molecular species. Histoenzymatic ultrastructural techniques show internal AChE in amacrine as well as in ganglion cell bodies, and external enzyme, specifically associated with synapses and axons, in the inner plexiform layer. The probable cooperation of the extracellular A12-forms and the membrane-bound G species (mainly G4) of the enzyme to the hydrolysis of acetylcholine (ACh) released into the external compartment is suggested and discussed.
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PMID:Compartmentalization of acetylcholinesterase in the chick retina. 270 46

Choline acetyltransferase (ChAT) activity, the sedimentation and solubility forms of acetylcholinesterase (AChE) as well as total (3H-quinuclidinyl benzilate, QNB) and M1 (3H-pirenzepine, PZ) muscarinic binding were investigated in the temporal cortex (TC) and nucleus caudatus (NC) of both non-demented and demented parkinsonian patients and controls. ChAT activity and low-salt-soluble and detergent-soluble AChE were lower in the TC of demented patients with Parkinson's disease than in controls. ChAT activity and the solubility forms of AChE in the NC did not differ between controls and parkinsonian patients. In the TC, the activity of the intermediate form of AChE was lower in parkinsonian patients, but the activity of the light form of AChE did not differ between controls and parkinsonian patients. In the TC of patients with Parkinson's disease the Bmax of 3H-QNB binding was slightly higher than in controls, but the Bmax of 3H-PZ binding did not differ between controls and parkinsonian patients. In the NC the Bmax of 3H-QNB binding was unchanged compared to that of the controls. The concomitant decrease of ChAT with soluble as well as membrane-bound tetrameric AChE suggests a close relationship between ChAT and tetrameric form of AChE. M1 receptors (3H-PZ binding sites) are not affected in the TC, but are decreased in the NC of demented parkinsonian patients. This decrease may be secondary to the loss of dopaminergic neurons projecting from the substantia nigra to the striatum.
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PMID:Different forms of brain acetylcholinesterase and muscarinic binding in Parkinson's disease. 272 71

Incubation of membranes derived from sarcotubular system of rabbit skeletal muscle with increasing concentrations of Triton X-100 produced both stimulation of the AChE activity and solubilization of this enzyme. Mild proteolytic treatment of microsomal membranes produced a several fold activation of the still membrane-bound acetylcholinesterase (AChE) activity. Attempts were made to solubilize AChE from microsomal membranes by proteolytic treatment. About 30-40% of the total enzyme activity could be solubilized by means of trypsin or papain. Short trypsin treatment of the microsomal membranes produced first an activation of the membrane-bound enzyme followed by solubilization. Incubation of muscle microsomes for a short time with papain yielded a significant portion of soluble enzyme. Membrane-bound enzyme activation was measured after a prolonged incubation period. These results are compared with those of solubilization obtained by treatment of membranes with progressive concentrations of Triton X-100. The occurrence of molecular forms in protease-solubilized AChE was investigated by means of centrifugation analysis and slab gel electrophoresis. Centrifugation on sucrose gradients revealed two main components of 4.4S and 10-11S in either trypsin or papain-solubilized AChE. These components behaved as hydrophilic species whereas the Triton solubilized AChE showed an amphipatic character. Application of slab gel electrophoresis showed the occurrence of forms with molecular weights of 350,000; 175,000; 165,000; 85,000 and 76,000. The stimulation of membrane-bound AChE by detergents or proteases would indicate that most of the enzyme molecules or their active sites are sequestered into the lipid bilayer through lipid-protein or protein-protein interactions and these are broken by proteolytic digestion of the muscle microsomes.
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PMID:Proteolytic stimulation and solubilization of membrane-bound acetylcholinesterase from muscle sarcotubular system. 272 20

The actions of ethanol on the structural stability of acetylcholine receptor (AchR)-enriched membrane vesicles and the activity of various molecular forms of acetylcholinesterase (AchE) were investigated, using the receptor and the enzyme isolated from the electric organ of Torpedo californica. In the presence of ethanol up to 200 mM, the thermogram of AchR-enriched membranes exhibited no significant decrease in the temperature (td) of receptor transition at 57 degrees C, but a decrease in the enthalpy change (delta Hd) indicated a slight ethanol-induced structural perturbation. The presence of 12.5 nmol alpha-bungarotoxin also caused a decrease in delta Hd. A complete loss of the receptor transition was observed at a higher concentration 500 nmol of alpha-bungarotoxin and no recovery of the transition was found with the addition of 200 mM ethanol. The results suggested a noncompetitive interaction of ethanol with the receptor. In the presence of 200-1000 mM ethanol, the activity of two soluble forms of AchE, a higher (117 S) aggregate and a lower (10 S) aggregate was not significantly affected. Comparing the activity of these two aggregates over a wide concentration range of ethanol (200-2000 mM) revealed no obvious difference in the level of ethanol effect between them. However, after removal of ethanol, the higher aggregate form of AchE exhibited a greater recoverability of the activity, suggesting a possible slightly greater structure-functional stability for it. Studies of soluble AchE and membrane-bound AchE showed that the presence of 200 or 600 mM ethanol caused a greater level of inhibition in membrane-bound enzyme than in soluble enzyme, possible due to a disruption of protein-lipid interaction needed to maintain the conformation of membrane-bound AchE. Interestingly, at a much higher concentration of ethanol (2.0 M), membrane-bound AchE became more resistant to ethanol than did the soluble forms of AchE. In this case, the effective concentration of ethanol felt by the enzyme was expected to be less for membrane-bound AchE, owing to ethanol's solubility in lipids.
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PMID:The effects of ethanol on the structural stability of acetylcholine receptor and the activity of various molecular forms of acetylcholinesterase. 277 89

Synaptic membranes were isolated from 2 and 4-month-old rats, pair-fed controls (PF), prenatally (PAE) or pre + postnatally (PPAE) exposed to alcohol, and the activities of some membrane-bound enzymes were measured. We found a 22-36% reduction in the levels of the (Na + K)ATPase, Ca++ATPase, acetylcholinesterase and 5'-nucleotidase from PAE rats. This reduction was greater in PPAE animals. The transition temperature in Arrhenius plots of the synaptosomal (Na + K)ATPase activity from PPAE rats was lower than in control rat membranes, indicating an alteration of lipid-protein interactions. No change in transition temperature was noted in PAE animals. Also, there was a decreased cholesterol content in PPAE synaptic membranes, vs. controls, while there was no change in PAE membranes. Kinetic parameters of the synaptosomal (Na + K)ATPase from PPAE rats, revealed a decrease in the Km and Vmax for potassium. These findings indicate that prenatal alcohol exposure probably delays synaptic development, whereas continued alcohol exposure during lactation may, in addition, alter the physicochemical structure of synaptic membranes.
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PMID:Synaptic membrane alterations in rats exposed to alcohol. 282 96

The sensitivity of acetylcholinesterases (AChEs) from Musca domestica and from Drosophila melanogaster to the phosphatidylinositol-specific phospholipase C from Bacillus cereus and to the glycosylphosphatidylinositol-specific phospholipase C from Trypanosoma brucei was investigated. B. cereus phospholipase C solubilizes membrane-bound AChE, and both phospholipases convert amphiphilic AChEs into hydrophilic forms of the enzyme. The lipases uncover an immunological determinant that is found on other glycosylphosphatidylinositol-anchored membrane proteins after the same treatment. This immunological determinant is also present on the native hydrophilic form of AChE. The polypeptide bearing the active site of the membrane-bound enzyme migrates faster during sodium dodecyl sulfate-polyacrylamide gel electrophoresis than the same polypeptide from the soluble enzyme. We conclude that AChE from insect brain is attached to membranes via a glycophospholipid anchor. This anchor is covalently linked to the polypeptide bearing the active esterase site of the enzyme and can be cleaved by an endogenous lipase.
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PMID:Acetylcholinesterases from Musca domestica and Drosophila melanogaster brain are linked to membranes by a glycophospholipid anchor sensitive to an endogenous phospholipase. 283 Dec 98

The acetylcholinesterase activity of the fruit fly, Drosophila melanogaster, was characterized biochemically. The activity is associated with a glycoprotein which is divided between a detergent-extractable membrane-bound fraction and a soluble fraction. The acetylcholinesterase activity is concentrated in the head of the insect. Through pharmacological methods, greater than 95% of the cholinesterase is judged to be true acetylcholinesterase, and not pseudocholinesterase. As expected for an acetylcholinesterase, the enzyme has a high affinity for acetylthiocholine and is inhibited by excess concentrations of acetylthiocholine. The soluble enzyme is found predominantly as a 7.8 S form; a smaller amount of an approximately 6 S form is also present, and a greater than or equal to 14 S form may exist. The detergent-solubilized acetylcholinesterase has a sedimentation coefficient of 7.5 S in the presence of detergent. The thermal inactivation rates for the soluble and the membrane bound enzymes are markedly different.
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PMID:Characterization of acetylcholinesterase activity from Drosophila melanogaster. 286 Oct 64

Activity of membrane-bound enzymes, passive penetration of ions in dose-dependent loading with cholesterol, effect of cholesterol high concentrations on the metabolic patterns in cytosol, viscosity of cell suspension were studied in erythrocytes. Passive cotransport of H+ and Cl- ions via erythrocyte membrane was increased with augmentation in viscosity of the cell suspension. After loading with cholesterol activity of acetylcholinesterase was increased while ATPase and glyceraldehyde-3-phosphate dehydrogenase activities were decreased. The alteration in the enzymatic activity occurred on those sides of the membranes, where these enzymes were localized. Activity of lactate dehydrogenase was decreased in cytoplasm of erythrocytes. The alterations detected may be important in development of ischemic syndrome in hyperlipoproteinemia.
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PMID:[Activity of membrane-bound enzymes, indices of metabolism in the cytoplasm and various physico-chemical properties of erythrocytes with increased cholesterol level]. 293 99


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