Oxaloacetic acid

Oxaloacetic acid (also known as OAA) is a four-carbon molecule found in all living organisms. It is a key intermediate in various metabolic pathways, including the citric acid cycle, gluconeogenesis, and the alanine cycle.

Structure and properties[edit]

Oxaloacetic acid is a carboxylic acid with the chemical formula C4H4O5. It has a molecular weight of 132.07 g/mol. The molecule consists of a ketone group and two carboxylic acid groups. The pKa values of the carboxylic acid groups are 2.22 and 3.13, respectively.

Role in metabolism[edit]

Oxaloacetic acid plays a crucial role in several metabolic pathways. In the citric acid cycle, it combines with acetyl-CoA to form citric acid, which is then metabolized to produce energy. In gluconeogenesis, oxaloacetic acid is a key intermediate in the conversion of non-carbohydrate substrates into glucose. In the alanine cycle, it is converted into aspartic acid.

Synthesis[edit]

In biological systems, oxaloacetic acid is synthesized from pyruvic acid by the enzyme pyruvate carboxylase. It can also be synthesized from phosphoenolpyruvic acid by the enzyme phosphoenolpyruvate carboxykinase.