Acetylcholinesterase
Acetylcholinesterase, also known as AChE or acetylcholine acetylhydrolase, is an enzyme that degrades (through its hydrolytic activity) the neurotransmitter acetylcholine, producing choline and an acetate group. It is mainly found at neuromuscular junctions and cholinergic nervous system, where its activity serves to terminate synaptic transmission. AChE has a very high catalytic activity — each molecule of AChE degrades about 25000 molecules of acetylcholine per second. The choline produced by the action of AChE is recycled — it is transported, through reuptake, back into nerve terminals where it is used to synthesize new acetylcholine molecules.[1]
Acetylcholinesterase is also found on the red blood cell membranes, where it constitutes the Yt blood group antigen. Acetylcholinesterase exists in multiple molecular forms, which possess similar catalytic properties, but differ in their oligomeric assembly and mode of attachment to the cell surface.
In humans acetylcholinesterase is encoded by the ACHE gene.[2]
Species distribution
Acetylcholine is widely expressed in eukaryotes including at least some plants.[3]
AChE gene
In mammals, acetylcholinesterase is encoded by a single AChE gene while some invertebrates have multiple acetylcholinesterase genes. Diversity in the transcribed products from the sole mammalian gene arises from alternative mRNA splicing and post-translational associations of catalytic and structural subunits. There are three known forms: T (tail), R (read through), and H(hydrophobic).[4]
AChET
The major form of acetylcholinesterase found in brain, muscle, and other tissues, known as is the hydrophilic species, which forms disulfide-linked oligomers with collagenous, or lipid-containing structural subunits. In the neuromuscular junctions AChE expresses in asymmetric form which associates with ColQ or subunit. In the central nervous system it is associated with PRiMA which stands for Proline Rich Membrane anchor to form symmetric form. In either case, the ColQ or PRiMA anchor serves to maintain the enzyme in the intercellular junction, ColQ for the neuromuscular junction and PRiMA for synapses.
AChEH
The other, alternatively-spliced form expressed primarily in the erythroid tissues, differs at the C-terminus, and contains a cleavable hydrophobic peptide with a PI-anchor site. It associates with membranes through the phosphoinositide (PI) moieties added post-translationally.[5]
AChER
The third type has, so far, only been found in Torpedo sp. and mice although it is hypothesized in other species. It is thought to be involved in the stress response and, possibly, inflammation.[6]
AChE inhibitors
Acetylcholinesterase is the target of many Alzheimer's Dementia drugs and sage oil, nerve gases(particularly the organophosphates (e.g. Sarin) and insecticides (e.g. carbaryl)). These agents — known as cholinesterase inhibitors — block the function of acetylcholinesterase and thus cause more acetylcholine to accumulate in the synaptic cleft.
Excess acetylcholine causes neuromuscular paralysis (i.e. interminable muscle contractions) throughout the entire body, leading to death by asphyxiation.[1]
Cholinesterase inhibitor may also be used in treatment of Lewy Body Dementia.
Cholinesterase inhibitors may be reversible inhibitors or quasi-irreversible inhibitors.
An endogenous inhibitor of AChE in neurons is Mir-132 microRNA, which may limit inflammation in the brain by silencing the expression of this protein and allowing ACh to act an in anti-inflammatory capacity.[7]
It has been shown that the main active ingredient in cannabis, tetrahydrocannibinol, is a competitive inhibitor of acetylcholinesterase.[8]
See also
References
- ^ a b Dale Purves, George J. Augustine, David Fitzpatrick, William C. Hall, Anthony-Samuel LaMantia, James O. McNamara, and Leonard E. White (2008). Neuroscience. 4th ed.. Sinauer Associates. pp. 121–2. ISBN 978-0-87893-697-7.
- ^ Ehrlich G, Viegas-Pequignot E, Ginzberg D, Sindel L, Soreq H, Zakut H (August 1992). "Mapping the human acetylcholinesterase gene to chromosome 7q22 by fluorescent in situ hybridization coupled with selective PCR amplification from a somatic hybrid cell panel and chromosome-sorted DNA libraries". Genomics 13 (4): 1192–7. doi:10.1016/0888-7543(92)90037-S. PMID 1380483.
- ^ Momonoki YS (May 1992). "Occurrence of Acetylcholine-Hydrolyzing Activity at the Stele-Cortex Interface". Plant Physiol. 99 (1): 130–133. doi:10.1104/pp.99.1.130. PMC 1080416. PMID 16668839. http://www.plantphysiol.org/cgi/pmidlookup?view=long&pmid=16668839.
- ^ Massoulié J, Perrier N, Noureddine H, Liang D, Bon S (2008). "Old and new questions about cholinesterases.". Chem Biol Interact 175 (1-3): 30–44. doi:10.1016/j.cbi.2008.04.039. PMID 18541228.
- ^ "Entrez Gene: ACHE acetylcholinesterase (Yt blood group)". http://www.ncbi.nlm.nih.gov/sites/entrez?Db=gene&Cmd=ShowDetailView&TermToSearch=43.
- ^ Dori A, Ifergane G, Saar-Levy T, Bersudsky M, Mor I, Soreq H, Wirguin I (2007). "Readthrough acetylcholinesterase in inflammation-associated neuropathies.". Life Sci 80 (24-25): 2369–74. doi:10.1016/j.lfs.2007.02.011. PMID 17379257.
- ^ Shaked I, Meerson A, Wolf Y, Avni R, Greenberg D, Gilboa-Geffen A, Soreq H (2009). "MicroRNA-132 potentiates cholinergic anti-inflammatory signaling by targeting acetylcholinesterase". Immunity 31 (6): 965–73. doi:10.1016/j.immuni.2009.09.019. PMID 20005135.
- ^ Eubanks LM, Rogers CJ, Beuscher AE 4th, Koob GF, Olson AJ, Dickerson TJ, Janda KD. (2006). "A molecular link between the active component of marijuana and Alzheimer's disease pathology.". Mol Pharm 3 (6): 773–7. doi:10.1021/mp060066m. PMC 2562334. PMID 17140265. http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2562334.
Further reading
- Silman I, Futerman AH (1988). "Modes of attachment of acetylcholinesterase to the surface membrane.". Eur. J. Biochem. 170 (1-2): 11–22. doi:10.1111/j.1432-1033.1987.tb13662.x. PMID 3319614.
- Sussman JL, Harel M, Frolow F, Oefner C, Goldman A, Toker L, Silman I. (1991). "Atomic structure of acetylcholinesterase from Torpedo californica: a prototypic acetylcholine-binding protein.". Science 253 (5022): 872–9. doi:10.1126/science.1678899. PMID 1678899.
- Soreq H, Seidman S (2001). "Acetylcholinesterase--new roles for an old actor.". Nat. Rev. Neurosci. 2 (4): 294–302. doi:10.1038/35067589. PMID 11283752.
- Shen T, Tai K, Henchman RH, McCammon JA (2003). "Molecular dynamics of acetylcholinesterase.". Acc. Chem. Res. 35 (6): 332–40. doi:10.1021/ar010025i. PMID 12069617.
- Pakaski M, Kasa P (2003). "Role of acetylcholinesterase inhibitors in the metabolism of amyloid precursor protein.". Current drug targets. CNS and neurological disorders 2 (3): 163–71. doi:10.2174/1568007033482869. PMID 12769797.
- Meshorer E, Soreq H (2006). "Virtues and woes of AChE alternative splicing in stress-related neuropathologies.". Trends Neurosci. 29 (4): 216–24. doi:10.1016/j.tins.2006.02.005. PMID 16516310.
- Ehrlich G, Viegas-Pequignot E, Ginzberg D, et al. (1992). "Mapping the human acetylcholinesterase gene to chromosome 7q22 by fluorescent in situ hybridization coupled with selective PCR amplification from a somatic hybrid cell panel and chromosome-sorted DNA libraries.". Genomics 13 (4): 1192–7. doi:10.1016/0888-7543(92)90037-S. PMID 1380483.
- Spring FA, Gardner B, Anstee DJ (1992). "Evidence that the antigens of the Yt blood group system are located on human erythrocyte acetylcholinesterase.". Blood 80 (8): 2136–41. PMID 1391965.
- Shafferman A, Kronman C, Flashner Y, et al. (1992). "Mutagenesis of human acetylcholinesterase. Identification of residues involved in catalytic activity and in polypeptide folding.". J. Biol. Chem. 267 (25): 17640–8. PMID 1517212.
- Getman DK, Eubanks JH, Camp S, et al. (1992). "The human gene encoding acetylcholinesterase is located on the long arm of chromosome 7.". Am. J. Hum. Genet. 51 (1): 170–7. PMC 1682883. PMID 1609795. http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=1682883.
- Li Y, Camp S, Rachinsky TL, et al. (1992). "Gene structure of mammalian acetylcholinesterase. Alternative exons dictate tissue-specific expression.". J. Biol. Chem. 266 (34): 23083–90. PMID 1744105.
- Velan B, Grosfeld H, Kronman C, et al. (1992). "The effect of elimination of intersubunit disulfide bonds on the activity, assembly, and secretion of recombinant human acetylcholinesterase. Expression of acetylcholinesterase Cys-580----Ala mutant.". J. Biol. Chem. 266 (35): 23977–84. PMID 1748670.
- Soreq H, Ben-Aziz R, Prody CA, et al. (1991). "Molecular cloning and construction of the coding region for human acetylcholinesterase reveals a G + C-rich attenuating structure.". Proc. Natl. Acad. Sci. U.S.A. 87 (24): 9688–92. doi:10.1073/pnas.87.24.9688. PMC 55238. PMID 2263619. http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=55238.
- Chhajlani V, Derr D, Earles B, et al. (1989). "Purification and partial amino acid sequence analysis of human erythrocyte acetylcholinesterase.". FEBS Lett. 247 (2): 279–82. doi:10.1016/0014-5793(89)81352-3. PMID 2714437.
- Lapidot-Lifson Y, Prody CA, Ginzberg D, et al. (1989). "Coamplification of human acetylcholinesterase and butyrylcholinesterase genes in blood cells: correlation with various leukemias and abnormal megakaryocytopoiesis.". Proc. Natl. Acad. Sci. U.S.A. 86 (12): 4715–9. doi:10.1073/pnas.86.12.4715. PMC 287342. PMID 2734315. http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=287342.
- Bazelyansky M, Robey E, Kirsch JF (1986). "Fractional diffusion-limited component of reactions catalyzed by acetylcholinesterase.". Biochemistry 25 (1): 125–30. doi:10.1021/bi00349a019. PMID 3954986.
- Gaston SM, Marchase RB, Jakoi ER (1982). "Brain ligatin: a membrane lectin that binds acetylcholinesterase.". J. Cell. Biochem. 18 (4): 447–59. doi:10.1002/jcb.1982.240180406. PMID 7085778.
- Ordentlich A, Barak D, Kronman C, et al. (1995). "Contribution of aromatic moieties of tyrosine 133 and of the anionic subsite tryptophan 86 to catalytic efficiency and allosteric modulation of acetylcholinesterase.". J. Biol. Chem. 270 (5): 2082–91. doi:10.1074/jbc.270.5.2082. PMID 7836436.
- Maruyama K, Sugano S (1994). "Oligo-capping: a simple method to replace the cap structure of eukaryotic mRNAs with oligoribonucleotides.". Gene 138 (1-2): 171–4. doi:10.1016/0378-1119(94)90802-8. PMID 8125298.
- Ben Aziz-Aloya R, Sternfeld M, Soreq H (1994). "Promoter elements and alternative splicing in the human ACHE gene.". Prog. Brain Res. 98: 147–53. PMID 8248502.
- Massoulie J, Pezzementi L, Bon S, Krejci E, Valette F (1993). "Molecular and Cellular Biology of Cholinesterases.". Prog. Brain Res. 93 (1): 31–91. doi:10.1016/0301-0082(93)90040-Y. PMID 8321908.
External links
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PDB gallery
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1b41: HUMAN ACETYLCHOLINESTERASE COMPLEXED WITH FASCICULIN-II, GLYCOSYLATED PROTEIN
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1f8u: CRYSTAL STRUCTURE OF MUTANT E202Q OF HUMAN ACETYLCHOLINESTERASE COMPLEXED WITH GREEN MAMBA VENOM PEPTIDE FASCICULIN-II
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1vzj: STRUCTURE OF THE TETRAMERIZATION DOMAIN OF ACETYLCHOLINESTERASE: FOUR-FOLD INTERACTION OF A WWW MOTIF WITH A LEFT-HANDED POLYPROLINE HELIX
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| 3.1.1: Carboxylic ester hydrolases |
Cholinesterase (Acetylcholinesterase, Butyrylcholinesterase) · Pectinesterase · 6-phosphogluconolactonase · PAF acetylhydrolase
Lipase (Bile salt-dependent, Gastric/Lingual, Pancreatic, Lysosomal, Hormone-sensitive, Endothelial, Hepatic, Lipoprotein, Monoacylglycerol, Diacylglycerol)
Phospholipase ( A1, A2, B)
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| 3.1.2: Thioesterase |
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| 3.1.3: Phosphatase |
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| 3.1.4: Phosphodiesterase |
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| 3.1.6: Sulfatase |
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Nuclease (includes
deoxyribonuclease and
ribonuclease) |
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B enzm: 1.1/2/3/4/5/6/7/8/10/11/13/14/15-18, 2.1/2/3/4/5/6/7/8, 2.7.10, 2.7.11-12, 3.1/2/3/4/5/6/7, 3.1.3.48, 3.4.21/22/23/24, 4.1/2/3/4/5/6, 5.1/2/3/4/99, 6.1-3/4/5-6
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| monoamine |
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| arginine→NO |
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| choline→Acetylcholine |
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mt, k, c/g/r/p/y/i, f/h/s/l/o/e, a/u, n, m
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k, cgrp/y/i, f/h/s/l/o/e, au, n, m, epon
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m(A16/C10),i(k, c/g/r/p/y/i, f/h/s/o/e, a/u, n, m)
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Agonists: 77-LH-28-1 • AC-42 • AC-260,584 • Aceclidine • Acetylcholine • AF30 • AF150(S) • AF267B • AFDX-384 • Alvameline • AQRA-741 • Arecoline • Bethanechol • Butyrylcholine • Carbachol • CDD-0034 • CDD-0078 • CDD-0097 • CDD-0098 • CDD-0102 • Cevimeline • cis-Dioxolane • Ethoxysebacylcholine • LY-593,039 • L-689,660 • LY-2,033,298 • McNA343 • Methacholine • Milameline • Muscarine • NGX-267 • Ocvimeline • Oxotremorine • PD-151,832 • Pilocarpine • RS86 • Sabcomeline • SDZ 210-086 • Sebacylcholine • Suberylcholine • Talsaclidine • Tazomeline • Thiopilocarpine • Vedaclidine • VU-0029767 • VU-0090157 • VU-0152099 • VU-0152100 • VU-0238429 • WAY-132,983 • Xanomeline • YM-796
Antagonists: 3-Quinuclidinyl Benzilate • 4-DAMP • Aclidinium Bromide • Anisodamine • Anisodine • Atropine • Atropine Methonitrate • Benactyzine • Benzatropine (Benztropine) • Benzydamine • BIBN 99 • Biperiden • Bornaprine • CAR-226,086 • CAR-301,060 • CAR-302,196 • CAR-302,282 • CAR-302,368 • CAR-302,537 • CAR-302,668 • CS-27349 • Cyclobenzaprine • Cyclopentolate • Darifenacin • DAU-5884 • Dimethindene • Dexetimide • DIBD • Dicyclomine (Dicycloverine) • Ditran • EA-3167 • EA-3443 • EA-3580 • EA-3834 • Elemicin • Etanautine • Etybenzatropine (Ethylbenztropine) • Flavoxate • Himbacine • HL-031,120 • Ipratropium bromide • J-104,129 • Hyoscyamine • Mamba Toxin 3 • Mamba Toxin 7 • Mazaticol • Mebeverine • Methoctramine • Metixene • Myristicin • N-Ethyl-3-Piperidyl Benzilate • N-Methyl-3-Piperidyl Benzilate • Orphenadrine • Otenzepad • Oxybutynin • PBID • PD-102,807 • PD-0298029 • Phenglutarimide • Phenyltoloxamine • Pirenzepine • Piroheptine • Procyclidine • Profenamine • RU-47,213 • SCH-57,790 • SCH-72,788 • SCH-217,443 • Scopolamine (Hyoscine) • Solifenacin • Telenzepine • Tiotropium bromide • Tolterodine • Trihexyphenidyl • Tripitamine • Tropatepine • Tropicamide • WIN-2299 • Xanomeline • Zamifenacin; Others: 1st Generation Antihistamines ( Brompheniramine, chlorphenamine, cyproheptadine, dimenhydrinate, diphenhydramine, doxylamine, mepyramine/ pyrilamine, phenindamine, pheniramine, tripelennamine, triprolidine, etc) • Tricyclic Antidepressants ( Amitriptyline, doxepin, trimipramine, etc) • Tetracyclic Antidepressants ( Amoxapine, maprotiline, etc) • Typical Antipsychotics ( Chlorpromazine, thioridazine, etc) • Atypical Antipsychotics ( Clozapine, olanzapine, quetiapine, etc)
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Agonists: 5-HIAA • A-84,543 • A-366,833 • A-582,941 • A-867,744 • ABT-202 • ABT-418 • ABT-560 • ABT-894 • Acetylcholine • Altinicline • Anabasine • Anatoxin-a • AR-R17779 • Butyrylcholine • Carbachol • Cotinine • Cytisine • Decamethonium • Desformylflustrabromine • Dianicline • Dimethylphenylpiperazinium • Epibatidine • Epiboxidine • Ethanol • Ethoxysebacylcholine • EVP-4473 • EVP-6124 • Galantamine • GTS-21 • Ispronicline • Lobeline • MEM-63,908 (RG-3487) • Nicotine • NS-1738 • PHA-543,613 • PHA-709,829 • PNU-120,596 • PNU-282,987 • Pozanicline • Rivanicline • Sazetidine A • Sebacylcholine • SIB-1508Y • SIB-1553A • SSR-180,711 • Suberylcholine • TC-1698 • TC-1734 • TC-1827 • TC-2216 • TC-5214 • TC-5619 • TC-6683 • Tebanicline • Tropisetron • UB-165 • Varenicline • WAY-317,538 • XY-4083
Antagonists: 18-Methoxycoronaridine • α-Bungarotoxin • α-Conotoxin • Alcuronium • Amantadine • Anatruxonium • Atracurium • Bupropion (Amfebutamone) • Chandonium • Chlorisondamine • Cisatracurium • Coclaurine • Coronaridine • Dacuronium • Decamethonium • Dextromethorphan • Dextropropoxyphene • Dextrorphan • Diadonium • DHβE • Dimethyltubocurarine (Metocurine) • Dipyrandium • Dizocilpine (MK-801) • Doxacurium • Duador • Esketamine • Fazadinium • Gallamine • Hexafluronium • Hexamethonium (Benzohexonium) • Ibogaine • Isoflurane • Ketamine • Kynurenic acid • Laudexium (Laudolissin) • Levacetylmethadol • Malouetine • Mecamylamine • Memantine • Methadone • Methorphan (Racemethorphan) • Methyllycaconitine • Metocurine • Mivacurium • Morphanol (Racemorphanol) • Neramexane • Nitrous Oxide • Pancuronium • Pempidine • Pentamine • Pentolinium • Phencyclidine • Pipecuronium • Radafaxine • Rapacuronium • Rocuronium • Surugatoxin • Suxamethonium (Succinylcholine) • Thiocolchicoside • Toxiferine • Trimethaphan • Tropeinium • Tubocurarine • Vecuronium • Xenon
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1-(-Benzoylethyl)pyridinium • 2-(α-Naphthoyl)ethyltrimethylammonium • 3-Chloro-4-stillbazole • 4-(1-Naphthylvinyl)pyridine • Acetylseco hemicholinium-3 • Acryloylcholine • AF64A • B115 • BETA • CM-54,903 • N,N-Dimethylaminoethylacrylate • N,N-Dimethylaminoethylchloroacetate
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AChE inhibitors
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Cymserine * Many of the acetylcholinesterase inhibitors listed above act as butyrylcholinesterase inhibitors.
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