Coenzyme A
![]() | |
![]() | |
![]() | |
Identifiers | |
---|---|
3D model (JSmol)
|
|
ECHA InfoCard | 100.001.472 |
MeSH | Coenzyme+A |
PubChem CID
|
|
| |
Properties | |
C21H36N7O16P3S | |
Molar mass | 767.535 |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
|
Coenzyme A (CoA, CoASH, or HSCoA) is a coenzyme, notable for its role in the synthesis and oxidation of fatty acids, and the oxidation of pyruvate in the citric acid cycle. All sequenced genomes encode enzymes that use coenzyme A as a substrate and around 4% of cellular enzymes use it (or a thioester, such as acetyl-CoA) as a substrate. It is adapted from cysteamine, pantothenate, and adenosine triphosphate.
Biosynthesis
Coenzyme A is synthesized in a five-step process from pantothenate:
- Pantothenate (vitamin B5) is phosphorylated to 4'-phosphopantothenate by the enzyme pantothenate kinase (PanK; CoaA; CoaX)
- A cysteine is added to 4'-phosphopantothenate by the enzyme phosphopantothenoylcysteine synthetase (PPC-DC; CoaB) to form 4'-phospho-N-pantothenoylcysteine (PPC)
- PPC is decarboxylated to 4'-phosphopantetheine by phosphopantothenoylcysteine decarboxylase (CoaC)
- 4'-phosphopantetheine is adenylylated to form dephospho-CoA by the enzyme phosphopantetheine adenylyl transferase (CoaD)
- Finally, dephospho-CoA is phosphorylated using ATP to coenzyme A by the enzyme dephosphocoenzyme A kinase (CoaE).
Function
Since coenzyme A is chemically a thiol, it can react with carboxylic acids to form thioesters, thus functioning as an acyl group carrier. It assists in transferring fatty acids from the cytoplasm to mitochondria. A molecule of coenzyme A carrying an acetyl group is also referred to as acetyl-CoA. When it is not attached to an acyl group it is usually referred to as 'CoASH' or 'HSCoA'.
Coenzyme A is also the source of the phosphopantetheine group that is added as a prosthetic group to proteins such as acyl carrier protein and formyltetrahydrofolate dehydrogenase.[1][2]
List of coenzyme A activated acyl groups
- Acetyl-CoA
- Propionyl-CoA
- Acetoacetyl-CoA
- Coumaroyl-CoA (used in flavonoid and stilbenoid biosynthesis)
- Acyl derived from dicarboxylic acids
- Malonyl-CoA
- Succinyl-CoA
- Hydroxymethylglutaryl-CoA (used in isoprenoid biosynthesis)
- Pimelyl-CoA (used in biotin biosynthesis)
Additional images
-
Coenzyme A
References
- ^ Elovson J, Vagelos PR (1968). "Acyl carrier protein. X. Acyl carrier protein synthetase". J. Biol. Chem. 243 (13): 3603–11. PMID 4872726.
{{cite journal}}
: Unknown parameter|month=
ignored (help) - ^ Strickland KC, Hoeferlin LA, Oleinik NV, Krupenko NI, Krupenko SA (2010). "Acyl carrier protein-specific 4'-phosphopantetheinyl transferase activates 10-formyltetrahydrofolate dehydrogenase". J. Biol. Chem. 285 (3): 1627–33. doi:10.1074/jbc.M109.080556. PMID 19933275.
{{cite journal}}
: Unknown parameter|month=
ignored (help)CS1 maint: multiple names: authors list (link) CS1 maint: unflagged free DOI (link)
Bibliography
- Karl Miller (1998). Beta Oxidation of Fatty Acids. Retrieved May 18, 2005.
- Charles Ophard (2003). Acetyl-CoA Crossroads. Retrieved May 18, 2005.
- Lehninger: Principles of Biochemistry, 4th edition, David L. Nelson, Michael M. Cox
- http://www.elmhurst.edu/~chm/vchembook/621fattyacidrx.html
![](http://upload.wikimedia.org/wikipedia/en/thumb/4/4a/Commons-logo.svg/30px-Commons-logo.svg.png)