Oxaloacetic acid

From Wikipedia, the free encyclopedia

Oxaloacetic acid
Oxaloacetic acid
Chemical name Oxobutanedioic acid
Other names Oxaloacetic acid
Oxalacetic acid
Oxosuccinic acid
Chemical formula C4H4O5
Molecular mass 132.07 g/mol
Melting point 161 °C
Density  ? g/cm3
pKa value 2.22
3.89
CAS number [328-42-7]
EINECS number 206-329-8
SMILES OC(C(CC(O)=O)=O)=O
Thermodynamic data
Standard enthalpy
of formation
Δfsolid
-943.21 kJ/mol
Standard enthalpy
of combustion
Δcsolid
-1205.58 kJ/mol
Disclaimer and references

Oxaloacetic acid, also known as oxosuccinic acid or oxalacetic acid, is a four-carbon dicarboxylic acid appearing as an intermediate of the citric acid cycle and gluconeogenesis. In vivo, oxaloacetate (the ionised form of oxaloacetic acid) is formed by the oxidation of L-malate, catalysed by malate dehydrogenase, and reacts with Acetyl-CoA to form citrate, catalysed by citrate synthase. It is also formed in the mesophyll of plants by the condensation of CO2 with phosphoenolpyruvate, catalysed by oxaloacetate decarboxylase. It can be formed from pyruvate as an 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 pKa value of 13.02. The enzyme fumarase A from E. coli catalyses the conversion between the keto and enol forms.

Oxaloacetic acid is unstable in solution, decomposing to pyruvic acid by decarboxylation over a period of hours (room temperature) or days (0°C). Refrigerator storage of the solid is recommended for long periods.

[edit] See also


 v  d  e 
Citric Acid Cycle Metabolic Pathway
Oxaloacetate Malate Fumarate Succinate Succinyl CoA
Acetyl CoA NADH + H+ NAD+ H2O FADH2 FAD CoA + ATP Pi + ADP
+ H2O NADH + H+ + CO2
CoA NAD+
H2O H2O NADP+ NADPH + H+ CO2
Citrate cis-Aconitate Isocitrate Oxalosuccinate Alpha-ketoglutarate


This metabolism related compound article is a stub. You can help Wikipedia by expanding it.
This article is of interest to the Metabolic Pathways WikiProject.
In other languages