What is ketone carboxylic acid

Keto acids, in German-speaking countries often as Oxo acids are carboxylic acids that also contain a carbonyl group. Their properties are determined by the distance between the two functional groups. The distance is often denoted by Greek letters (α = adjacent, β = 1,3 distance, etc.).


In cellular processes, keto acids play a central role in amino acid metabolism and in maintaining the redox status. α-Keto acids contain the carbon structure of the analogous amino acid. β-keto acids are energy-rich (unstable) metabolites that react under CO2-Can drive loss (decarboxylation).


α-keto acids

Pyruvic acid with its salts, the pyruvates, is the simplest α-keto acid. Under the action of pyruvate decarboxylase, pyruvic acid can convert into acetaldehyde (and CO2) or in the pyruvate dehydrogenase multi-enzyme complex to acetyl-CoA (and CO2) are decarboxylated. In the citric acid cycle there is another reaction based on the same basic principle: the decarboxylation of the α-ketoglutarate to succinyl-CoA. Coenzymes this as "oxidative decarboxylation“Designated processes are thiamine diphosphate and NAD+, possibly coenzyme A.

Also in vitro An analogous reaction can be observed: The relatively weak C-C bond in the group R-CO-COOH can be cleaved by adding concentrated sulfuric acid and carbon monoxide and the corresponding carboxylic acid R-COOH are formed.

Another typical reaction of α-keto acids is transamination, which involves a reciprocal amination with simultaneous deamination of glutamic acid without the occurrence of free ammonia. Pyruvate becomes alanine, oxaloacetate (a compound that is both α- and β-keto acid) becomes aspartate, and α-ketoglutarate becomes glutamate, while the coenzyme is pyridoxal phosphate.

β-keto acids

The simplest β-keto acid is the volatile acetoacetic acid. β-Keto acids are mostly unstable substances that disintegrate with decarboxylation. This process can take place spontaneously, also catalyzed biochemically in the cell. One example is the decarboxylation of oxaloacetate in gluconeogenesis by phosphoenolpyruvate carboxykinase (PEP-CK) or by the malate enzyme (ME).

γ-keto acids

The simplest γ-keto acid is levulinic acid.

See also

Category: Fabric group