Acetylcholinesterase

In biochemistry, cholinesterase is a term which refers to one of the two enzymes: File links The following pages link to this file: Cholinesterase Categories: Free use images | Protein images ... File links The following pages link to this file: Cholinesterase Categories: Free use images | Protein images ... Biochemistry is the chemistry of life. ... Ribbon diagram of the catalytically perfect enzyme TIM. Factor D enzyme crystal prevents the immune system from inappropriately running out of control. ...

• 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) also known as plasma cholinesterase, butyrylcholinesterase, or (most formally) acylcholine acylhydrolase, found primarily in the liver

Both of these compounds catalyze 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. EC numbers (Enzyme Commission numbers) are a numerical classification scheme for enzymes, based on the chemical reactions they catalyze. ... // Description Human red blood cells Red blood cells are the most common type of blood cell and are the vertebrate bodys principal means of delivering oxygen to body tissues via the blood. ... Red blood cells (erythrocytes) are present in the blood and help carry oxygen to the rest of the cells in the body Blood is a circulating tissue composed of fluid plasma and cells (red blood cells, white blood cells, platelets). ... 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. ... Synapses allow nerve cells to communicate with one another through axons and dendrites, converting electrical signals into chemical ones. ... EC numbers (Enzyme Commission numbers) are a numerical classification scheme for enzymes, based on the chemical reactions they catalyze. ... The liver is an organ in vertebrates, including humans. ... A catalyst (Greek: καταλύτης, catalytēs) is a substance that accelerates the rate (speed) of a chemical reaction without itself being transformed or consumed by the reaction (see also catalysis). ... Hydrolysis is a chemical process in which a molecule is cleaved into two parts by the addition of a molecule of water. ... Neurotransmitters are chemicals that are used to relay, amplify and modulate electrical signals between a neuron and another cell. ... The chemical compound acetylcholine, often abbreviated as ACh, was the first neurotransmitter to be identified. ... Choline (trimethyl ethanolamine) is a quaternary saturated amine with the chemical formula (CH3)3N+CH2CH2OH. It was discovered by Strecker in 1862 and chemically synthesized in 1866. ... The chemical compound acetic acid (from the Latin word acetum, meaning vinegar), systematically called ethanoic acid, is the acid that gives vinegar its sour taste and very pungent smell when at high concentrations. ... A synapse is cholinergic if it uses acetylcholine as its neurotransmitter. ...

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 3D structure of acetylcholinesterase was first determined in 1991 by Sussman et al. In biochemistry, a substrate is a molecule which is acted upon by an enzyme. ... Butyrylcholine is an acetylcholine-like molecule, with activation of some of the same receptors as acetylcholine. ...

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 anaesthetic agent succinylcholine 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. ...

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 snake venom, sarin and VX). 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, or neurons, usually by interacting with membrane proteins and ion channels. ... This article is about the toxin. ... Sarin or GB (O-Isopropyl methylphosphonofluoridate) is an extremely toxic substance. ... 1. ...

Outside of biochemical warfare, anticholinesterases are used are also used in anesthesia or in the treatment of myasthenia gravis, glaucoma and Alzheimer's disease. 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). ... Cetacaine, a topical anesthetic Anesthesia (AE), also anaesthesia (BE), is the process of blocking the perception of pain and other sensations. ... Myasthenia gravis (MG, Latin: grave muscle weakness) is a neuromuscular disease leading to fluctuating weakness and fatiguability. ...

Reference

• 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.

External link

• Movies showing the structure of acetylcholinesterase and intereactions with various inhibitors.
• Acetylcholinesterase: Molecule of the Month on PDB