ImageFile = Acetyl-CoA-2D.svg
ImageSize = 350px
ImageFile2 = Acetyl-CoA-3D-balls.png
Section1 = Chembox Identifiers
CASNo = 72-89-9
PubChem = 181
SMILES = O=C(NCCSC(=O)C)CCNC
(=O) [C@H] (O)C(C)(C) COP(=O)(O)OP(=O)
(O)OC [C@H] 1O [C@H] ( [C@H] (O) [C@@H] 1OP(=O)
MeSHName = Acetyl+Coenzyme+A
Section2 = Chembox Properties
Formula = C23H38N7O17P3S
MolarMass = 809.572
Section3 = Chembox Hazards
Acetyl-CoA is an important molecule in metabolism, used in many biochemical reactions. Its main use is to convey the
carbon atoms within the acetylgroup to the citric acid cycleto be oxidized for energy production. In chemical structure, acetyl-CoA is the thioesterbetween coenzyme A(a thiol) and acetic acid(an acylgroup carrier). Acetyl-CoA is produced during the second step of aerobic cellular respiration, pyruvate decarboxylation, which occurs in the matrix of the mitochondria. Acetyl-CoA then enters the citric acid cycle.
Acetyl-CoA is also an important component in the biogenic synthesis of the neurotransmitter
acetylcholine. Choline, in combination with Acetyl-CoA, is catalyzed by the enzyme choline acetyltransferaseto produce acetylcholine and a coenzyme abyproduct.
Pyruvate dehydrogenase and pyruvate formate lyase reactions
The oxidative conversion of
pyruvateinto acetyl-CoA is referred to as the pyruvate dehydrogenase reaction. It is catalyzed by the pyruvate dehydrogenase complex. Other conversions between pyruvate and acetyl-CoA are possible. For example, pyruvate formate lyasedisproportionates pyruvate into acetyl-CoA and formic acid. The pyruvate formate lyase reaction does not involve any net oxidation or reduction.
Fatty acid metabolism
In animals, acetyl-CoA is central to the balance between
carbohydrate metabolismand fatmetabolism (see fatty acid synthesis). In normal circumstances, acetyl-CoA from fatty acid metabolism feeds into the citric acid cycle, contributing to the cell's energy supply. In the liver, when levels of circulating fatty acids are high, the production of acetyl-CoA from fat breakdown exceeds the cellular energy requirements. To make use of the energy available from the excess acetyl-CoA, ketone bodiesare produced which can then circulate in the blood.
In some circumstances, this can lead to the presence of very high levels of ketone bodies in the
blood, a condition called ketosis. Benign dietary ketosis can safely occur in people following low-carbohydrate diets, which cause fats to be metabolised as a major source of energy. This is different from ketosisbrought on as a result of starvation and ketoacidosis, a dangerous condition that can affect diabetics.
In plants, de novo fatty acid synthesis occurs in the plastids. Many seeds accumulate large reservoirs of seed oils to support
germinationand early growth of the seedling before it is a net photosynthetic organism. Fatty acids are incorporated into membrane lipids, the major component of most membranes.
* Two acetyl-CoA can be condensed to create
acetoacetyl-CoA, the first step in the HMG-CoA/ mevalonic acid pathwayleading to synthesis of isoprenoids. In animals HMG-CoA is a vital precursor to cholesteroland ketone synthesis.
* Acetyl-CoA is also the source of the acetyl group incorporated onto certain lysine residues of histone and non-histone proteins in the post-translational modification
acetylation, a reaction catalyzed by acetyltransferases.
* In plants and animals, cytosolic acetyl-CoA is synthesized by
ATP citrate lyase[http://www.plantphysiol.org/cgi/content/full/130/2/740] . When glucose is abundant in the blood of animals, it is converted via glycolysisin the cytosolto pyruvate, and thence to acetyl-CoA in the mitochondrion. The excess of acetyl-CoAresults in production of excess citrate, which is exported into the cytosol to give rise to cytosolic acetyl-CoA.
* Acetyl-CoA can be
carboxylatedin the cytosol by acetyl-CoA carboxylase, giving rise to malonyl-CoA, a substrate required for synthesis of flavonoids and related polyketides, for elongation of fatty acids to produce waxes, cuticle, and seed oils in members of the Brassicafamily, and for malonation of proteins and other phytochemicals [http://www.plantcell.org/cgi/content/full/17/1/182] .
* In plants, these include
sesquiterpenes, brassinosteroids (hormones), and membrane sterols.
Citric acid cycle
HMG-CoA reductase pathway
Fatty acid metabolism
Acetyl Co-A synthetase
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Look at other dictionaries:
Acetyl-coA — Acétyl coenzyme A L acétyl coenzyme A (acétyl coA ou acétyl CoA), molécule à haut potentiel d hydrolyse est au centre d un carrefour métabolique. En tant qu il peut être lié à la dégradation du pyruvate, soit être le résultat de la beta oxydation … Wikipédia en Français
Acétyl-CoA — Acétyl coenzyme A L acétyl coenzyme A (acétyl coA ou acétyl CoA), molécule à haut potentiel d hydrolyse est au centre d un carrefour métabolique. En tant qu il peut être lié à la dégradation du pyruvate, soit être le résultat de la beta oxydation … Wikipédia en Français
acetyl CoA — kō ā n ACETYL COENZYME A * * * ac·e·tyl CoA (asґə təl) (as″ə tēlґ ko aґ) acetyl coenzyme A … Medical dictionary
acetyl-CoA — Condensation product of coenzyme A and acetic acid, symbolized as CoAS∼COCH3; intermediate in transfer of two carbon fragment, notably in its entrance into the tricarboxylic acid cycle and in fatty acid synthesis. SYN: acetyl coenzyme A … Medical dictionary
Acetyl-CoA — Strukturmodell des Coenzym A. Strukturformel von Coenzym A. Coenzym A (auch Koenzym A, kurz CoA oder CoASH) ist ein Coenzym, das zur „Aktivierung“ von Alkansäuren und deren … Deutsch Wikipedia
acetyl-CoA — • acetyl coenzyme A … Dictionary of medical acronyms & abbreviations
acetyl coA — ə¦sēd.əlˌkōˈā; ¦asəd.əl , əˌtēl noun Usage: usually capitalized C Etymology: acetyl coenzyme A : acetyl coenzyme A … Useful english dictionary
acetyl CoA — noun Date: 1951 acetyl coenzyme A … New Collegiate Dictionary
acetyl-coA — a·ce·tyl co·A (ə sētʹl kōʹāʹ, ăs ĭ tl ) n. See acetyl coenzyme A. * * * … Universalium
acetyl CoA — Abbreviation for acetyl co enzyme A … Glossary of Biotechnology