Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.1.1.7 (acetylcholinesterase)
 28,390 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

By treatment with phosphatidylinositol-specific phospholipase C (PIPLC), we obtained several candidates of glycosylphosphatidylinositol (GPI)-anchored proteins such as 55, 42, 40, and 30 kDa from bovine erythrocyte membrane, in addition to the well-known GPI-anchored protein acetylcholinesterase. In these proteins, the presence of myo-inositol was confirmed by gas chromatography (GC)-mass spectrometry. Among them, the 42-kDa protein was further analyzed by electrospray-ionization (ESI)-mass spectrometry (MS) after hydrolysis by lysyl endoprotease. By liquid chromatography (LC)-ESI-MS analysis, C-terminal peptides bearing the products of GPI (Ct. GPI-peptides) were effectively detected by combination with in-source collision and multifunctional scanning for the several characteristic fragment ions from the GPI-anchor structure. Existence of microheterogeneity was also observed in the Ct. GPI-peptides from the 42-kDa protein. This result was confirmed by analysis with time-of-flight (TOF)-MS. Furthermore, one of the Ct. GPI-peptides was analyzed in ESI-MS-MS mode. Characteristic fragment ions were effectively detected by collision-induced decay. By the result of MS-MS analysis, this GPI-anchor structure was revealed to contain additional N-acetyl hexosamine. By the above-mentioned method, the C-terminal GPI-anchor structure can be easily identified from the target protein even if its amino acid sequence data are not available.
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PMID:Identification of a new glycosylphosphatidylinositol-anchored 42-kDa protein and its C-terminal peptides from bovine erythrocytes by gas chromatography-, time-of-flight-, and electrospray-ionization-mass spectrometry. 1004 99

Acoustic neurinomas were sequentially extracted with saline and saline-Triton X-100 buffers. Detergent was required to detach the bulk of acetylcholinesterase (AChE), but butyrylcholinesterase (BuChE) was mostly released with saline buffer. Sedimentation analysis and hydrophobic chromatography revealed that neurinomas contain principally amphiphilic AChE tetramers, dimers and monomers, and hydrophilic BuChE tetramers. The AChE dimers and monomers remained amphiphilic after incubation with phosphatidylinositol-specific phospholipase C (PIPLC), after or without prior treatment with alkaline hydroxylamine, which shows that, in contrast to the meningioma AChE dimers and monomers, the neurinoma isoforms are devoid of glycolipid. Neurinoma AChE reacted with the antibodies HR2 and AE1 raised against AChE from human brain or erythrocyte, whereas BuChE bound to a sheep antiserum.
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PMID:Characterization of molecular forms of acetyl- and butyrylcholinesterase in human acoustic neurinomas. 1053 May 19

In the cercarial and schistosomal stages of the life cycle of the trematode Schistosoma mansoni, acetylcholinesterase occurs as two principal molecular forms (both globular), present in approximately equal amounts, with sedimentation coefficients of 6.5 S and 8 S. The 6.5 S form is solubilized by bacterial phosphatidylinositol-specific phospholipase C from intact schistosomula. It is thus located on the outer surface of the schistosomal tegument and is most probably analogous to the glycosylphosphatidylinositol-anchored G(2) form of acetylcholinesterase found in the electric organ of Torpedo, on the surface of mammalian erythrocytes, and elsewhere. Both forms are fully solubilized by the non-ionic detergent Triton X-100. Upon passing such a detergent extract over a heparin-Sepharose column, only the 8 S form was retained on the column. The bound acetylcholinesterase could be progressively eluted by increasing the salt concentration, with approx. 0.5-0.6 M NaCl being needed for complete elution. Selective inhibition experiments carried out on live parasites using the covalent acetylcholinesterase inhibitor echothiophate (phospholine), which does not penetrate the tegument, selectively inhibited the 6.5 S form, but not the 8 S form, suggesting an internal location for the latter. Monoclonal antibodies raised against S. mansoni acetylcholinesterase also distinguished between the two forms. Thus monoclonal antibody SA7 bound the 6.5 S form selectively, whereas SA57 recognized the 8 S form. The selective binding of the 8 S form to heparin suggests that, within the parasite, this form may be associated with the extracellular matrix of the musculature.
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PMID:Acetylcholinesterase from Schistosoma mansoni: interaction of globular species with heparin. 1058 85

In order to know whether the histopathological changes of liver, which accompany muscular dystrophy, affect the synthesis of cholinesterases, the distribution and glycosylation of acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE) forms in normal (NL) and dystrophic Lama2(dy) mouse liver (DL) were investigated. About half of liver AChE, and 25% of BuChE were released with a saline buffer (fraction S(1)), and the rest with a saline-Brij 96 buffer (S(2)). Abundant light (G(2)(A) and G(1)(A)) AChE (87%) and BuChE (93%) forms, and a few G(4)(H) and G(4)(A) ChE species were identified in liver. The dystrophic syndrome had no effect on solubilization or composition of ChE forms. Most of the light AChE and BuChE species (>95%) were bound by octyl-Sepharose, while most light AChE forms (80%), but not BuChE isoforms (15%), were retained in phenyl-agarose. About half of the AChE dimers lost their amphiphilic anchor with phosphatidylinositol-specific phospholipase C (PIPLC), and the fraction of PIPLC-resistant species increased in DL. AChE T and R transcripts were detected by reverse transcriptase-polymerase chain reaction (RT-PCR) of liver RNA. ChE components of liver, erythrocyte, and plasma were distinguished by their amphiphilic properties and interaction with lectins. The dystrophic syndrome increased the liver content of the light AChE forms with Lens culinaris agglutinin (LCA) reactivity. The abundance of ChE tetramers in plasma and their small amount in liver suggest that after their assembly in liver they are rapidly secreted, while the light species remain associated to hepatic membranes.
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PMID:Muscular dystrophy alters the processing of light acetylcholinesterase but not butyrylcholinesterase forms in liver of Lama2(dy) mice. 1100 95

Differences in the glycosylation of acetylcholinesterase (AChE) subunits which form the dimers of mouse erythrocyte and a suitable procedure to purify the enzyme by affinity chromatography in edrophonium-Sepharose are described. AChE was extracted ( approximately 80%) from erythrocytes with Triton X-100 and sedimentation analyses showed the existence of amphiphilic AChE dimers in the extract. The AChE dimers were converted into monomers by reducing the disulfide bond which links the enzyme subunits. Lectin interaction studies revealed that most of the dimers were bound by concanavalin A (Con A) (90-95%), Lens culinaris agglutinin (LCA) (90-95%), and wheat germ (Triticum vulgaris) agglutinin (WGA) (70-75%), and a small fraction by Ricinus communis agglutinin (RCA(120)) (25-30%). The lower level of binding of the AChE monomers with WGA (55-60%), and especially with RCA (10-15%), with respect to the dimers, reflected heterogeneity in the sugar composition of the glycans linked to each AChE subunit in dimers. Forty per cent of the amphiphilic AChE dimers lost the glycosylphosphatidylinositol (GPI) and, therefore, were converted into hydrophilic forms, by incubation with phosphatidylinositol-specific phospholipase C (PIPLC), which permitted their separation from the amphiphilic variants in octyl-Sepharose. Only the hydrophilic dimers, either isolated or mixed with the amphiphilic forms, were bound by edrophonium-Sepharose, which allowed their purification (4800-fold) with a specific activity of 7700 U/mg protein. The identification of a single protein band of 66 kDa in gel electrophoresis demonstrates that the procedure can be used for the purification of GPI-anchored AChE, providing that the attached glycolipid domain is susceptible to PIPLC.
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PMID:Purification and properties of hydrophilic dimers of acetylcholinesterase from mouse erythrocytes. 1267 81

The presence of acetylcholinesterase (AChE) mRNA and activity in the tissues and cells involved in immune responses prompted us to investigate the level and pattern of AChE components in spleen. AChE activity was higher in mouse spleen (0.46 +/- 0.13 micromol of acetylthiocholine split per hour and per mg protein) than in muscle or heart, but lower than in brain. The spleen was essentially free of butyrylcholinesterase (BuChE) activity. About 40% of spleen AChE was extracted with a saline buffer, and a further 40% with 1% Triton X-100. Sedimentation analyses, the splitting of subunits in AChE dimers, phosphatidylinositol-specific phospholipase C (PIPLC) exposure, and phenyl-agarose chromatography showed that hydrophilic (G1H, 43%) and amphiphilic AChE monomers (G1A, 36%), as well as amphiphilic dimers (G2A, 21%), occurred in spleen. All these molecules bound to fasciculin-2-Sepharose, although the extent of binding was higher for G1H (77%) than for G1A (63%) or G2A (48%) forms. Differences in the extent to which wheat germ lectin (WGA) adsorbed with AChE of mouse spleen and of erythrocyte allowed us to discard the blood origin of spleen AChE activity. A 62 kDa protein was labeled in spleen samples using antibodies against human AChE. The protein was attributed to AChE monomers since its size was the same, regardless of whether disulfide bonds were reduced or not. Since cholinergic stimulation modulates proliferation/maturation of lymphoid cells, AChE may be important for regulating the level of acetylcholine (ACh) in the neighborhood of cholinergic receptors (AChR) in spleen and other lymphoid tissues.
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PMID:Molecular properties of acetylcholinesterase in mouse spleen. 1508 30

Half of congenital muscular dystrophy cases arise from laminin alpha2 (merosin) deficiency, and merosin-deficient mice (Lama2dy) exhibit a dystrophic phenotype. The abnormal development of thymus in Lama2dy mice, the occurrence of acetylcholinesterase (AChE) in the gland and the impaired distribution of AChE molecules in skeletal muscle of the mouse mutant prompted us to compare the levels of AChE mRNAs and enzyme species in thymus of control and Lama2dy mice. AChE activity in normal thymus (mean +/- SD 1.42 +/- 0.28 micromol acetylthiocholine/h/mg protein, U/mg) was decreased by approximately 50% in dystrophic thymus (0.77 +/- 0.23 U/mg) (p = 0.007), whereas butyrylcholinesterase activity was little affected. RT-PCR assays revealed variable levels of R, H and T AChE mRNAs in thymus, bone marrow and spinal cord. Control thymus contained amphiphilic AChE dimers (G2A, 64%) and monomers (G1A, 19%), as well as hydrophilic tetramers (G4H, 9%) and monomers (G1H, 8%). The dimers consisted of glycosylphosphatidylinositol-anchored H subunits. Western blot assays with anti-AChE antibodies suggested the occurrence of inactive AChE in mouse thymus. Despite the decrease in AChE activity in Lama2dy thymus, no differences between thymuses from control and dystrophic mice were observed in the distribution of AChE forms, phosphatidylinositol-specific phospholipase C sensitivity, binding to lectins and size of AChE subunits.
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PMID:Muscular dystrophy by merosin deficiency decreases acetylcholinesterase activity in thymus of Lama2dy mice. 1613 75

Two acetylcholinesterase (EC 3.1.1.7) membrane forms AChE(m1) and AChE(m2), have been characterised in the honey bee head. They can be differentiated by their ionic properties: AChE(m1) is eluted at 220 mM NaCl whereas AChE(m2) is eluted at 350 mM NaCl in anion exchange chromatography. They also present different thermal stabilities. Previous processing such as sedimentation, phase separation, and extraction procedures do not affect the presence of the two forms. Unlike AChE(m1), AChE(m2) presents reversible chromatographic elution properties, with a shift between 350 to 220 mM NaCl, depending on detergent conditions. Purification by affinity chromatography does not abolish the shift of the AChE(m2) elution. The similar chromatographic behaviour of soluble AChE strongly suggests that the occurrence of the two membrane forms is not due to the membrane anchor. The two forms have similar sensitivities to eserine and BW284C51. They exhibit similar electrophoretic mobilities and present molecular masses of 66 kDa in SDS-PAGE and a sensitivity to phosphatidylinositol-specific phospholipase C in non-denaturing conditions, thus revealing the presence of a glycosyl-phosphatidylinositol anchor. We assume that bee AChE occurs in two distinct conformational states whose AChE(m2) apparent state is reversibly modulated by the Triton X-100 detergent into AChE(m1).
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PMID:Existence of two membrane-bound acetylcholinesterases in the honey bee head. 1796 29

A glycolipid anchorage for acetylcholinesterase (AChE) has been found in some tissues. In this paper, the possibility of such an anchorage has been explored in mammalian muscle membranes. We report that a phosphatidylinositol-specific phospholipase C (PIPLC) solubilizes AChE from microsomal membranes of mouse intercostal muscle. Among the several molecular forms of AChE, PIPLC specifically releases in a dose dependent manner one molecular form which migrates on linear sucrose gradients as a single peak of sedimentation coefficient 6.3 s. In other subcellular membrane fractions, including motor endplate enriched fraction, PIPLC fails to solubilize AChE. This type of membrane glycolipid mediated anchorage for AChE is then only detectable in a precise region of skeletal muscle.
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PMID:A dimeric form of acetylcholinesterase anchored through a glycolipid in mouse skeletal muscle. 1965 Oct 88


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