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)

Enzyme activities (acetylcholinesterase, fluorescein diacetate hydrolase, superoxide dismutase), membrane protein band 4.1a/4.1b ratio and density of various fractions of rabbit erythrocytes separated did not show differences between various fractions of erythrocytes separated by free-flow electrophoresis. Also, electric field deflection of lightest and densest fractions of erythrocytes did not differ. These results point to the lack of changes in surface charge density during in vivo erythrocyte aging.
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PMID:Erythrocyte behavior in free-flow electrophoresis is independent of erythrocyte age. 815 21

Previous studies showed that anaesthesia with the barbiturate Thiopental induces an increase in membrane fluidity and a decrease in acetylcholinesterase activity in syncytiotrophoblast plasma membranes (SPM) obtained from placentas after Cesarean section. The aim of the present work was to compare the effect of a local anaesthetic (bupivacaine hydrochloride, trade name Marcaine) on SPM in vivo and to establish whether the anaesthetic is still present in the membrane after tissue preparation. The acetylcholinesterase activity was lower in Marcaine-anaesthetized SPM (27 +/- 3 against 39 +/- 6 in the control). The Marcaine action on the SPM can be ascribed to a competitive inhibition, similar to that reported for Thiopental. Fluorescence studies of the order parameter P showed it to be higher in SPM obtained from control (0.253 +/- 0.012) than in SPM obtained from Marcaine-exposed membranes (0.240 +/- 0.015). The local anaesthetic is still present in the SPM after their preparation (20.1 ng per mg membrane protein). It appears that the local anaesthetic exhibits an effect similar to that of the general anaesthetic, apparently due to binding to the membrane.
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PMID:Local anaesthetic effects on trophoblast membrane fluidity. 848 67

The action of peroxynitrite on human erythrocytes and erythrocyte membranes was studied. Peroxynitrite (0.1-2 mM) induced a transient decrease of intracellular reduced glutathione, oxidized membrane protein -SH groups, initiated membrane lipid peroxidation and inactivated erythrocyte membrane acetylcholinesterase and ATPase activities. Membranes exposed to peroxynitrite showed aggregation and nitration of proteins and changes in protein organization detectable with a maleimide spin label.
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PMID:Effect of peroxynitrite on erythrocytes. 889 70

Tetracaine-induced biphasic structure-functional alterations were investigated in acetylcholinesterase (AChE)-associated membrane vesicles from the electric organ of Torpedo californica. Enzyme assays showed that tetracaine exhibits a biphasic effect on the activity of membrane-bound AChE: increasing it at low concentrations (< 12 mM) and decreasing it at high concentrations (> 12 mM). Fluorescence-polarization experiments demonstrated that tetracaine affects the fluidity of lipid hydrocarbon chains of these membranes in a biphasic manner: increasing it at < 20 mM and decreasing it at > 20 mM. This small molecule also alters the fluidity of the negatively charged lipid head group: increasing it at < 13 mM and remaining essentially at the same level at > 13 mM. The positively charged lipid head group is unaffected. Contrasting effects on AChE activity with changes in membrane fluidity showed that [tetracaine] for AChE activity is comparable to that for the fluidity of the negatively charged lipid head group (12 mM versus 13 mM), but lower than that for a biphasic effect on the fluidity of lipid hydrocarbon chains (12 mM versus 20 mM). Differential scanning microcalorimetry showed that, due to membrane protein-lipid interaction, the lipid-phase transition temperature (tml) is higher for AChE-associated membrane vesicles than for isolated lipids from these membranes. An overall disordering of the membranes by tetracaine, as inferred from the lowering of tml, was also demonstrated. These findings suggested that binding of tetracaine to the lipid polar head group and membrane protein-lipid interaction may contribute to a higher [tetracaine] in inducing a comparable biphasic effect on membrane fluidity. At high [tetracaine], charge interactions between the tetracaine cation and the negatively charged lipid head group may result in a new lipid phase in the membranes, which could reverse the increase in membrane fluidity, resulting in the observed biphasic effect. Although both tetracaine and alcohol are amphiphilic species, they exhibit distinctive structure-functional effects on the membranes, as shown by comparing the results obtained on tetracaine with those previously reported for alcohol. The present observations may have significant physiological implications and may be of importance in understanding the biochemical effects of tetracaine in correlation with its physiological impact.
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PMID:Elucidation of biphasic alterations on acetylcholinesterase (AChE) activity and membrane fluidity in the structure-functional effects of tetracaine on AChE-associated membrane vesicles. 950 Aug 47

Sodium fluorescein angiography is a widely used routine ophthalmological diagnostic procedure which enables the study of chorioretinal microcirculation and consists of the injection of sodium fluorescein into the systemic bloodstream. The aim of the present study was to evaluate whether or not fluorescein interferes with erythrocyte properties during the angiographic procedure. In a group of 37 patients, 26 with non-insulin-dependent diabetes mellitus (DM) with and without retinopathy, and 11 without diabetes mellitus (non-DM) although affected by other ophthalmological diseases, all undergoing routine angiography, blood samples were drawn before (T0) and 30 min (T30) after fluorescein injection. The erythrocyte aggregation index (EAI), membrane lipid fluidity and erythrocyte acetylcholinesterase activity were determined in both groups. After fluorescein injection there was no statistical change in EAI and erythrocyte membrane fluidity in either group. Erythrocyte acetylcholinesterase activity, a marker of membrane protein integrity, decreased significantly (p < 0.01) in the DM group. Membrane lipid fluidity did not change with fluorescein injection, however (i) in the DM group erythrocyte membranes became more rigid than in the non-DM (DPH: p < 0.01); (ii) EAI and membrane lipid fluidity became significantly correlated (r = 0.6263, p < 0.05) in non-DM patients at T30. In conclusion, fluorescein administration for angiographic procedures seems to interact with erythrocyte membrane, namely, in diabetic patients, which may interfere with the blood flow in the microcirculation.
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PMID:The effect of sodium fluorescein angiography on erythrocyte properties. 969 34

By histochemical and immunohistochemical methods, the presence of cholinergic-like molecules has previously been demonstrated in Paramecium primaurelia, and their functional role in mating-cell pairing was suggested. In this work, both true acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE) activities were electrophoretically investigated, and the presence of molecules immunologically related to BuChE was checked by immunoblotting. The AChE activity, shown in the membrane protein fraction of mating-competent cells and in the cytoplasmic fraction of immature cells, is due to a 260-kDa molecular form, similar to the membrane-bound tetrameric form present in human erythrocytes. This AChE activity does not appear in either the cytoplasmic fraction of mating-competent cells or in the membrane protein fraction of immature cells. No evidence was found for the presence or the activity of BuChE-like molecules. The role of AChE in P. primaurelia developmental cycle is discussed.
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PMID:Evidence for the presence of a mammalian-like cholinesterase in Paramecium primaurelia (Protista, Ciliophora) developmental cycle. 999 Jul 39

Incubation of erythrocytes with liposomes results in the release of shed vesicles rich in glycosyl-phosphatidylinositol (GPI)-anchored proteins but poor in transmembranous proteins. We investigated the mechanisms of membrane protein polarization by examining the effect of the interaction between spectrin and membrane proteins on the release of a transmembranous protein, band 3, and a GPI-anchored protein, acetylcholinesterase (AChE), from erythrocyte ghosts. Polymerization of spectrin resulted in a 30-fold decrease in the released amount of band 3 per constant amount of shed vesicles but did not affect the amount of released AChE per constant amount of shed vesicles. On the other hand, the amount of released band 3 per constant amount of shed vesicles increased by cleaving the cytoplasmic part of band 3. Our results first demonstrated that the diffusibility of membrane proteins determined by steric hindrance between membrane proteins and protein mesh primarily determines the ease of localization of membrane proteins into shed vesicles. Taken together with the recent biophysical studies, we built a "fence selection model" that retrograding spectrin mesh sweeps diffusing band 3 molecules from the tip of the membrane crenated area toward the entry of the crenated area, but not AChE molecules. Our study describes a novel method for isolation of a large number of vesicles containing special and intact membrane proteins from cells not by using detergents or organic solvents, but by utilizing the fence effect between the cytoskeleton and membrane proteins.
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PMID:Mechanism of selective release of membrane proteins from human erythrocytes in the presence of liposomes. 1089 54

Analysis of the expressed protein complement of cells requires knowledge of the diversity of post-translational modifications that can occur and which can be transient or permanent. The modifications range from amino acid changes through to the addition of macromolecules: lipid, carbohydrate or protein. Many variants of the common amino acids can occur, which can affect the structure or function of the protein. The major class of modification, however, is represented by glycosylation, N-linked, O-linked, or glycosylphosphatidylinositol(GPI)-linked. Such modifications have roles in protein stability and folding, targeting and recognition. Glycosylated proteins can be found in all cellular compartments and, intracellularly, O-GlcNAc modification is commonplace. Lipid modification of proteins (acylation, prenylation, GPI-anchoring) is also common, resulting in membrane association, and can play an important role in cell signalling. Targeting and turnover of proteins can also be mediated via covalent protein addition, for example by members of the ubiquitin family. Limited proteolysis as a post-translational modification will be discussed, focusing on the family of membrane protein secretases, in particular in relation to the Alzheimer's amyloid precursor protein. Finally, acetylcholinesterase will be used as a model example to illustrate the diversity of modifications occurring on a single protein.
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PMID:Post-translational modifications of proteins: acetylcholinesterase as a model system. 1167 79

Glycosylphosphatidylinositol (GPI)-anchored proteins are ubiquitous in eukaryotes. The minimum conserved GPI core structure of all GPI-anchored glycans has been determined as EtN-PO4-6Manalpha1-2Manalpha1-6Manalpha1-4GlcN-myo-inositol-PO3H. Human placental alkaline phosphatase (AP) has been reported to be a GPI-anchored membrane protein. AP carries one N-glycan, (NeuAcalpha2-->3)2Gal2GlcNAc2Man3GlcNAc(+/-Fuc)GlcNAc, and a GPI anchor, which contains an ethanolamine phosphate diester group, as a side chain. However, we found that both sialidase-treated soluble AP (sAP) and its GPI-anchored glycan bound to a Psathyrella velutina lectin (PVL)-Sepharose column, which binds beta-GlcNAc residues. PVL binding of asialo-sAP and its GPI-anchored glycan was diminished by digestion with diplococcal beta-N-acetylhexosaminidase or by mild acid treatment. After sequential digestion of asialo-sAP with beta-N-acetylhexosaminidase and acid phosphatase, the elution patterns on chromatofocusing gels were changed in accordance with the negative charges of phosphate residues. Trypsin-digested sAP was analyzed by liquid chromatography/electrospray ionization mass spectrometry, and the structures of two glycopeptides with GPI-anchored glycans were confirmed as peptide-EtN-PO4-6Manalpha1-->2(GlcNAcbeta1-PO4-->6)Manalpha1-6(+/-EtN-PO4-->)Manalpha1-->4GlcN, which may be produced by endo-alpha-glucosaminidase. In addition to AP, GPI-anchored carcinoembryonic antigen, cholinesterase, and Tamm-Horsfall glycoprotein also bound to a PVL-Sepharose column, suggesting that the beta-N-acetylglucosaminyl phosphate diester residue is widely distributed in human GPI-anchored glycans. Furthermore, we found that the beta-N-acetylglucosaminyl phosphate diester residue is important for GPI anchor recognition of aerolysin, a channel-forming toxin derived from Aeromonas hydrophila.
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PMID:A beta-N-acetylglucosaminyl phosphate diester residue is attached to the glycosylphosphatidylinositol anchor of human placental alkaline phosphatase: a target of the channel-forming toxin aerolysin. 1285 98

Amyloid-beta (Abeta) is the principal protein constituent of 'senile plaques' and is a suspected mediator in Alzheimer's disease (AD). Senile plaques also contain acetylcholinesterase (AChE; EC 3.1.1.7), which may have a role in promoting Alphabeta-toxicity. We have found that Alphabeta can affect AChE expression in a neuron-like line, the N1E.115 neuroblastoma cell. When 1 micro mAlphabeta 1-42 or 25-35 was added for 24 h to differentiating N1E.115 in culture, AChE activity increased 30-40% in adherent cells, and 100% or more in nonadherent cells. The changes in both tetrameric (G4) and monomeric (G1) AChE forms were comparable. Turnover studies indicated that the elevation of AChE activity reflected slowed AChE degradation rather than accelerated synthesis. With a similar time course, Alphabeta also increased the quantity of muscarinic receptors on the plasma membrane. Immunocytochemistry for a lysosomal membrane protein (LAMP-1) indicated no change in abundance or localization of lysosomes in treated cells. But decreased labeling by pH-sensitive fluorescent dye pointed to an impairment of lysosomal acidification. We consider that the alteration of AChE expression after Alphabeta-exposure could reflect lysosomal dysfunction, and might itself enhance Alphabeta-toxicity.
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PMID:Amyloid-beta increases acetylcholinesterase expression in neuroblastoma cells by reducing enzyme degradation. 1287 88


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