Oxalacetic acid

Oxaloacetic acid (also known as oxalacetic acid) is a four-carbon molecule often involved in metabolic processes within living organisms. It is a key intermediate in the citric acid cycle, which is a central metabolic pathway in all aerobic organisms.

Structure and properties

Oxaloacetic acid is a carboxylic acid that consists of four carbon atoms, four oxygen atoms, and six hydrogen atoms. It has two carboxyl groups, which give it acidic properties. The molecule can exist in a keto form and an enol form, with the keto form being more stable and therefore more common.

Role in metabolism

In the citric acid cycle, oxaloacetic acid reacts with acetyl CoA to form citrate, in a reaction catalyzed by the enzyme citrate synthase. This is the first step of the cycle, which is central to cellular respiration in aerobic organisms. Oxaloacetic acid is regenerated at the end of the cycle, allowing it to be used again in the next round of the cycle.

Oxaloacetic acid is also involved in gluconeogenesis, a metabolic pathway that results in the generation of glucose from non-carbohydrate carbon substrates. In this process, oxaloacetic acid is converted into phosphoenolpyruvate, a reaction catalyzed by the enzyme PEP carboxykinase.

Health implications

Abnormal levels of oxaloacetic acid in the body can be indicative of certain health conditions. For example, high levels can be a sign of diabetes or liver disease, while low levels can indicate malnutrition or vitamin B6 deficiency.

See also

• Citric acid cycle
• Gluconeogenesis
• Metabolism