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| Names | |
|---|---|
| IUPAC name S-methoxy-hydroxyphosphoryl]oxy-hydroxyphosphoryl]oxy-2-hydroxy-3,3-dimethylbutanoyl]amino]propanoylamino]ethyl] propanethioate | |
| Other names Propionyl Coenzyme A; Propanoyl Coenzyme A | |
| Identifiers | |
| CAS Number | |
| 3D model (JSmol) | |
| ChemSpider | |
| ECHA InfoCard | 100.005.698 
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| MeSH | propionyl-coenzyme+A |
| PubChem CID | |
| CompTox Dashboard (EPA) | |
InChI
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SMILES
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| Properties | |
| Chemical formula | C24H40N7O17P3S |
| Molar mass | 823.60 g/mol |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C , 100 kPa).
 Y verify (what is ?)
Infobox references
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Propionyl-CoA is a coenzyme A derivative of propionic acid.
Metabolism in animals
Production
There are several different ways in which it is formed:
- It is formed as a product of beta-oxidation of odd-chain fatty acids.
- It is also a product of metabolism of isoleucine and valine.
- It is a product of alpha-ketobutyric acid, which in turn is a product of digestion of threonine and methionine.
Metabolic fate
In mammals, propionyl-CoA is converted to (S)-methylmalonyl-CoA by propionyl-CoA carboxylase, a biotin-dependent enzyme also requiring bicarbonate and ATP.
This product is converted to (R)-methylmalonyl-CoA by methylmalonyl-CoA racemase.
(R)-Methylmalonyl-CoA is converted to succinyl-CoA, an intermediate in the tricarboxylic acid cycle, by methylmalonyl-CoA mutase, an enzyme requiring cobalamin to catalyze the carbon-carbon bond migration.
The methylmalonyl-CoA mutase mechanism begins with the cleavage of the bond between the 5' CH2- of 5'-deoxyadenosyl and the cobalt, which is in its 3+ oxidation state (III), which produces a 5'-deoxyadenosyl radical and cabalamin in the reduced Co(II) oxidation state.
Next, this radical abstracts a hydrogen atom from the methyl group of methylmalonyl-CoA, which generates a methylmalonyl-CoA radical. It is believed that this radical forms a carbon-cobalt bond to the coenzyme which is then followed by the rearrangement of the substrate's carbon skeleton, thus producing a succinyl-CoA radical. This radical then goes on to abstract a hydrogen from the previously produced 5'-deoxyadenosine, again creating a deoxyadenosyl radical, which attacks the coenzyme to reform the initial complex.
A defect in methylmalonyl-CoA mutase enzyme results in methylmalonic aciduria, a dangerous disorder that causes a lowering of blood pH.
Metabolism in plants and insects
In plants and insects propionyl-CoA is metabolized to acetate in a very different way, similar to beta oxidation.
Not all details of this pathway have been worked out, but it appears to involve formation of acrylyl-CoA, then 3-hydroxypropionyl-CoA.
This is metabolized with loss of carbon 1 of 3-hydroxypropionyl-CoA as carbon dioxide, while carbon 3 becomes carbon 1 of acetate.
References
- Halarnkar P, Blomquist G (1989). "Comparative aspects of propionate metabolism". Comp. Biochem. Physiol., B. 92 (2): 227–31. doi:10.1016/0305-0491(89)90270-8. PMID 2647392.