Oxaloacetic acid
1110600
212592029
2008-05-15T12:53:42Z
AlnoktaBOT
3096998
robot Adding: [[ar:حمض أكسالوأسيتك]]
{{Chembox new
| Name = Oxaloacetic acid
| ImageFile = Oxaloacetic acid.png
| ImageName =
| IUPACName = Oxobutanedioic acid
| OtherNames = Oxaloacetic acid<br />Oxalacetic acid<br />Oxosuccinic acid
| Section1 = {{Chembox Identifiers
| CASNo = 328-42-7
| EINECS = 206-329-8
| SMILES = OC(C(CC(O)=O)=O)=O
}}
| Section2 = {{Chembox Properties
| Formula = C<sub>4</sub>H<sub>4</sub>O<sub>5</sub>
| MolarMass = 132.07 g/mol
| MeltingPt = 161 °C
| Density = ? g/cm<sup>3</sup>
}}
| Section4 = {{Chembox Thermochemistry
| DeltaHf = -943.21 kJ/mol
| DeltaHc = -1205.58 kJ/mol
}}
}}
'''Oxaloacetic acid''' is an [[organic compound]] with the chemical formula HO<sub>2</sub>CC(O)CH<sub>2</sub>CO<sub>2</sub>H. It also has other names (see Table) and its [[conjugate base]] is called "oxaloacetate." This four-[[carbon]] [[dicarboxylic acid]] is a protonated variant of oxaloacetate, which is an intermediate of the [[citric acid cycle]] and [[gluconeogenesis]]. Oxaloacetate forms upon [[oxidation]] of L-[[Malic acid|malate]], catalysed by [[malate dehydrogenase]], and reacts with [[Acetyl-CoA]] to form [[citrate]], catalysed by [[citrate synthase]]. It also forms in the [[mesophyll]] of plants by the condensation of [[Carbon dioxide|CO<sub>2</sub>]] with [[phosphoenolpyruvate]], catalysed by [[Phosphoenolpyruvate carboxykinase|PEP Carboxykinase]]. It can arise from [[pyruvate]] via an [[anaplerotic reactions|anaplerotic reaction]].
The [[enol]] forms of oxaloacetic acid are particularly stable, so much so that the two isomers have different melting points (152 °C ''cis'', 184 °C ''trans''). The enol proton has a [[Acid dissociation constant|pK<sub>a</sub> value]] of 13.02. The [[enzyme]] [[fumarase]] A from [[Escherichia coli|''E. coli'']] catalyses the conversion between the keto and enol forms.
Oxaloacetate is unstable in solution, decomposing to pyruvate by [[decarboxylation]] over a period of hours (room temperature) or days (0 °C). Refrigerated storage of the solid is therefore recommended.
[[Image:Oxaloac-malic.png|thumb|150px|left|Relationship of oxaloacetic acid, malic acid, and aspartic acid]]
<br clear = left/>
==References==
{{Unreferenced|date =September 2007}}
<references/>
{{citric acid cycle}}
{{metabolism-stub}}
[[Category:Citric acid cycle compounds]]
[[Category:Dicarboxylic acids]]
[[Category:Ketones]]
[[ar:حمض أكسالوأسيتك]]
[[cs:Kyselina oxaloctová]]
[[de:Oxalessigsäure]]
[[fr:Acide oxaloacétique]]
[[it:Acido ossalacetico]]
[[he:אוקסלואצטט]]
[[lv:Skābeņetiķskābe]]
[[hu:Oxálecetsav]]
[[ja:オキサロ酢酸]]
[[pl:Kwas szczawiooctowy]]
[[pt:Ácido oxaloacético]]
[[sv:Oxalättiksyra]]