In biochemistry, cholinesterase is an enzyme which catalyzes the hydrolysis of the neurotransmitter acetylcholine into choline and acetic acid, a reaction necessary to allow a cholinergic neuron to return to its resting state after activation. File links The following pages link to this file: Cholinesterase Categories: Free use images | Protein images ... Hugo is a masculine name. ... The Entrez logo The Entrez Global Query Cross-Database Search System allows access to databases at the National Center for Biotechnology Information (NCBI) website. ... The Mendelian Inheritance in Man project is a database that catalogues all the known diseases with a genetic component, and - when possible - links them to the relevant genes in the human genome. ... The National Center for Biotechnology Information (NCBI) is part of the US National Library of Medicine (NLM), which is a branch of the US National Institutes of Health. ... Swiss-Prot is a curated biological database of protein sequences created in 1986 by Amos Bairoch during his PhD and developed by the Swiss Institute of Bioinformatics and the European Bioinformatics Institute. ... The Enzyme Commission number (EC number) is a numerical classification scheme for enzymes, based on the chemical reactions they catalyze. ... Short and long arms Chromosome. ... Chromosome 7 is one of the 23 pairs of chromosomes in humans. ... Hugo is a masculine name. ... The Entrez logo The Entrez Global Query Cross-Database Search System allows access to databases at the National Center for Biotechnology Information (NCBI) website. ... The Mendelian Inheritance in Man project is a database that catalogues all the known diseases with a genetic component, and - when possible - links them to the relevant genes in the human genome. ... The National Center for Biotechnology Information (NCBI) is part of the US National Library of Medicine (NLM), which is a branch of the US National Institutes of Health. ... Swiss-Prot is a curated biological database of protein sequences created in 1986 by Amos Bairoch during his PhD and developed by the Swiss Institute of Bioinformatics and the European Bioinformatics Institute. ... The Enzyme Commission number (EC number) is a numerical classification scheme for enzymes, based on the chemical reactions they catalyze. ... Short and long arms Chromosome. ... Chromosome 3 is one of the 23 pairs of chromosomes in humans. ... Biochemistry is the study of the chemical processes and transformations in living organisms. ... It has been suggested that this article or section be merged into Catalysis. ... Hydrolysis is a chemical reaction or process in which a chemical compound reacts with water. ... Chemical structure of D-Aspartic Acid, a common Amino Acid neurotransmitter. ... The chemical compound acetylcholine, often abbreviated as ACh, was the first neurotransmitter to be identified. ... // Choline is a nutrient, essential for cardiovascular and brain function, and for cellular membrane composition and repair. ... Acetic acid, also known as ethanoic acid, is an organic chemical compound best recognized for giving vinegar its sour taste and pungent smell. ... A synapse is cholinergic if it uses acetylcholine as its neurotransmitter. ...

Types

There are two types:

• Acetylcholinesterase (EC 3.1.1.7) (AChE), also known as RBC cholinesterase, erythrocyte cholinesterase, or (most formally) acetylcholine acetylhydrolase, found primarily in the blood and neural synapses
• Pseudocholinesterase (EC 3.1.1.8) (BChE or BuChE), also known as plasma cholinesterase, butyrylcholinesterase, or (most formally) acylcholine acylhydrolase, found primarily in the liver

The difference between the two types of cholinesterase has to do with their respective preferences for substrates: the former hydrolyses acetylcholine more quickly; the latter hydrolyses butyrylcholine more quickly. The Enzyme Commission number (EC number) is a numerical classification scheme for enzymes, based on the chemical reactions they catalyze. ... Human red blood cells Red blood cells are the most common type of blood cell and the vertebrate bodys principal means of delivering oxygen from the lungs or gills to body tissues via the blood. ... Human blood smear: a - erythrocytes; b - neutrophil; c - eosinophil; d - lymphocyte. ... The nervous system of an animal coordinates the activity of the muscles, monitors the organs, constructs and processes input from the senses, and initiates actions. ... Illustration of the major elements in a prototypical synapse. ... The Enzyme Commission number (EC number) is a numerical classification scheme for enzymes, based on the chemical reactions they catalyze. ... The liver is an organ present in vertebrates and some other animals. ... In biochemistry, a substrate is a molecule upon which an enzyme acts. ... Butyrylcholine is an acetylcholine-like molecule, with activation of some of the same receptors as acetylcholine. ...

History

In 1968, Walo Leuzinger et al successfully purified and crystallized the enzyme from electric eels at Columbia University, NY. ^[1][2] Binomial name Electrophorus electricus (Linnaeus, 1766) The electric eel, Electrophorus electricus, is a species of fish. ...

The 3D structure of acetylcholinesterase was first determined in 1991 by Joel Sussman et al using protein from the Pacific electric ray.^[3] Joel L. Sussman is an Israeli crystallographer best known for his studies on acetylcholinesterase, a key protein involved in transmission of nerve signals. ... Binomial name Torpedo californica Ayres, 1855 The Pacific electric ray (Torpedo californica) is a species of electric ray native to the eastern Pacific Ocean. ...

Clinical significance

An absence or mutation of the pseudocholinesterase enzyme leads to a medical condition known simply as pseudocholinesterase deficiency. This is a silent condition that only manifests itself when people who have the deficiency receive the muscle relaxants succinylcholine or mivacurium during a surgery. Pseudocholinesterase deficiency is an inherited blood plasma enzyme abnormality. ... Suxamethonium chloride (also known as succinylcholine, or scoline) is a white crystalline substance, it is odourless and highly soluble in water. ... Mivacurium is a bisbenzylisoquinolinium based neuromuscular blocker or muscle relaxant. ...

Elevation of plasma pseudocholinesterase was observed in 90.5% cases of acute myocardial infraction.^[4]

Acetylcholinesterase is tested in early pregnancy. A sample of amniotic fluid is removed by amniocentesis. The presence of AChE in the amniotic fluid can confirm a neural tube defect, a common type of birth defect.[1] Amniocentesis, or an Amniotic Fluid Test (AFT), is a medical procedure used for prenatal diagnosis, in which a small amount of amniotic fluid is extracted from the amnion around a developing fetus. ... The neural tube is the embryonal structure that gives rise to the brain and spinal cord. ...

Cholinesterase inhibitors

A cholinesterase inhibitor (or "anticholinesterase") suppresses the action of the enzyme. Because of its essential function, chemicals that interfere with the action of cholinesterase are potent neurotoxins, causing excessive salivation and eye watering in low doses, followed by muscle spasms and ultimately death (examples are some snake venoms, and the nerve gases sarin and VX). One counteracting medication is pralidoxime. A cholinesterase inhibitor or anticholinesterase is a chemical that inhibits a cholinesterase enzyme from breaking down acetylcholine, so increasing both the level and duration of action of the neurotransmitter acetylcholine. ... A neurotoxin is a toxin that acts specifically on nerve cells – neurons – usually by interacting with membrane proteins and ion channels. ... Sarin, also known by its NATO designation of GB (O-Isopropyl methylphosphonofluoridate) is an extremely toxic substance whose sole application is as a nerve agent. ... The VX nerve agent is the most well-known of the V-series of nerve agents. ... Structure of the molecule pralidoxime Pralidoxime belongs to a family of compounds, called oximes that bind to organophosphate inactivated acetylcholinesterase. ...

Among the most common acetylcholinesterase inhibitors are phosphorus-based compounds which are designed to bind to the active site of the enzyme. The structural requirements are a phosphorus atom bearing two lipophilic groups, a leaving group (such as a halide or thiocyanate) and a terminal oxygen. The entry on Lawesson's reagent has some details on one sub-class of the phosphorus-based compounds. Ribbon diagram of the enzyme TIM, surrounded by the space-filling model of the protein. ... General Name, Symbol, Number phosphorus, P, 15 Chemical series nonmetals Group, Period, Block 15, 3, p Appearance waxy white/ red/ black/ colorless Standard atomic weight 30. ... This article or section does not cite its references or sources. ... A halide is a binary compound, of which one part is a halogen atom and the other part is an element or radical that is less electronegative than the halogen, to make a fluoride, chloride, bromide, iodide, or astatide compound. ... Thiocyanate (also known as sulphocyanate or thiocyanide) is both an anion SCN- and, in organic chemistry, a functional group: An example of the anion is found in potassium thiocyanate, KSCN. Thiocyanate is analogous to the cyanate ion, OCN-, wherein oxygen is replaced by sulfur. ... A polymer is a substance composed of molecules with large molecular mass consisting of repeating structural units, or monomers, connected by covalent chemical bonds. ... General Name, Symbol, Number oxygen, O, 8 Chemical series nonmetals, chalcogens Group, Period, Block 16, 2, p Appearance colorless (gas) very pale blue (liquid) Standard atomic weight 15. ... Lawessons reagent or LR is a chemical compound used in organic synthesis as a thiation agent. ...

Outside of biochemical warfare, anticholinesterases are also used in anesthesia or in the treatment of myasthenia gravis, glaucoma and Alzheimer's disease. Also, such compounds are used for killing insects in a range of products including sheep dip, organophosphate pesticides, and carbamate pesticides. In addition to acute poisoning as described above, a semi-acute poisoning characterized by strong mental disturbances can occur. Also, prolonged exposure can cause birth defects. Early detection of chemical agents Sociopolitical climate of chemical warfare While the study of chemicals and their military uses was widespread in China, the use of toxic materials has historically been viewed with mixed emotions and some disdain in the West (especially when the enemy were doing it). ... Anesthesia or anaesthesia (see spelling differences) has traditionally meant the condition of having the perception of pain and other sensations blocked. ... Myasthenia gravis (sometimes abbreviated MG; from the Greek myastheneia, lit. ... Orders Subclass Apterygota Symphypleona - globular springtails Subclass Archaeognatha (jumping bristletails) Subclass Dicondylia Monura - extinct Thysanura (common bristletails) Subclass Pterygota Diaphanopteroidea - extinct Palaeodictyoptera - extinct Megasecoptera - extinct Archodonata - extinct Ephemeroptera (mayflies) Odonata (dragonflies and damselflies) Infraclass Neoptera Blattodea (cockroaches) Mantodea (mantids) Isoptera (termites) Zoraptera Grylloblattodea Dermaptera (earwigs) Plecoptera (stoneflies) Orthoptera (grasshoppers, crickets... The term sheep dip refers to a solution of insecticide and fungicide which shepherds may use to protect their sheep from infestation. ... An organophosphate (sometimes abbreviated OP) is the general name for esters of phosphoric acid and is one of the organophosphorus compounds. ... Carbamates are a group of organic compounds sharing a common functional group with the general structure -NH(CO)O-. More precisely the carbamate group is considered an amide group with an alkoxy or hydroxy functional group next to the carbonyl group. ... A congenital disorder is a medical condition or defect that is present at or before birth (for example, congenital heart disease). ...

Pop Culture

• On season eight of Law and Order: SVU, Olivia Benson is taken to the hospital after being exposed to organophosphates, where she is told her cholinesterase level is low.

Detective Olivia Benson is a fictional character on the TV drama Law & Order: Special Victims Unit, portrayed by Mariska Hargitay. ... A physician visiting the sick in a hospital. ... An organophosphate (sometimes abbreviated OP) is the general name for esters of phosphoric acid and is one of the organophosphorus compounds. ...

Additional images

Acetylcholine Image File history File links Crest of Alcochete (Portugal) Author: Sérgio Horta The author has agreed to usage of his works under the GNU-FDL, as long as he is quoted as the source: Caro Senhor, Manuel Anastácio File links The following pages link to this file: Alcochete... The chemical compound acetylcholine, often abbreviated as ACh, was the first neurotransmitter to be identified. ...

Choline Image File history File links Download high-resolution version (1100x554, 10 KB) File links The following pages on the English Wikipedia link to this file (pages on other projects are not listed): Functional group Choline User:Benjah-bmm27/Old gallery ... // Choline is a nutrient, essential for cardiovascular and brain function, and for cellular membrane composition and repair. ...

Acetic acid Image File history File links This is a lossless scalable vector image. ... Acetic acid, also known as ethanoic acid, is an organic chemical compound best recognized for giving vinegar its sour taste and pungent smell. ...

Butyrylcholine Butyrylcholine is an acetylcholine-like molecule, with activation of some of the same receptors as acetylcholine. ...

Reference

1. ^ * Leuzinger W, Baker AL. Acetylcholinesterase, i. Large-scale purification, homogeneity, and amino acid analysis. Proc Natl Acad Sci U S A. 1967 Feb; 57(2): 446-451. PMCID: 335526
2. ^ Leuzinger W, Baker A L, Cauvin E. Acetylcholinesterase, II. Crystallization, Absorption Spectra, Isoionic Point. Proc Natl Acad Sci U S A, Vol. 59, No. 2 (Feb. 15, 1968), pp. 620-623. PMCID: 224717
3. ^ Sussman JL, Harel M, Frolow F, Oefner C, Goldman A, Toker L, Silman I. Atomic structure of acetylcholinesterase from Torpedo californica: a prototypic acetylcholine-binding protein. Science 1991;253:872-9. PMID 1678899.
4. ^ Textbook of Medical Biochemistry, MN Chatterjea & Rana Shinde, 6th Ed, 2005 (Pg 565)

External links

• Movies at weizmann.ac.il showing the structure of acetylcholinesterase and interactions with various inhibitors.
• PDB Molecule of the Month pdb54_1
• MeSH Acetylcholinesterase
• MeSH Pseudocholinesterase