OXALOACETIC ACID

(Redirected from Oxaloacetate)

'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 offormation ΔfH°solid	-943.21 kJ/mol
Standard enthalpy ofcombustion ΔcH°solid	-1205.58 kJ/mol

'Oxaloacetic acid' is an organic compound with the chemical formula HO₂CC(O)CH₂CO₂H. It also has other names (see Table) and is sometimes referred to as its conjugate base "oxaloacetate." This four-carbon dicarboxylic acid is an intermediate of the citric acid cycle and gluconeogenesis. Oxaloacetate forms upon oxidation of L-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 CO₂ with phosphoenolpyruvate, catalysed by oxaloacetate decarboxylase. It can be arise from pyruvate via 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 pK_a 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). Refrigerated storage of the solid is therefore recommended.

Contents

See also

See also