Keto acids or ketoacids (also called oxo acids or oxoacids) are organic compounds containing a carboxylic acid group and a ketone group.[1] in several cases the keto group is hydrated. Alpha-keto acids are particularly important in biology because they are involved in the Krebs citric acid cycle and in glycolysis.[2]

Common types of keto acids include:

Alpha-keto acids, alpha-keto acids or 2-oxides have a keto group adjacent to the carboxylic acid. They often appear as a result of oxidative deamination of amino acids and are in turn their precursors. Alpha-keto acids have broad chemical activity as acylating agents.[3] in addition, alpha-keto acids such as phenylpyruvic acid are endogenous sources of carbon monoxide (as a gas transmitter) and a pharmaceutical prodrug framework.[4] important representatives:
pyruvic acid, a common intermediate in metabolism.
oxalic acid, a component of the Krebs cycle.[5]
alpha-ketoglutarate, a 5-carbon keto acid derived from glutamic acid. Alpha-ketoglutarate is involved in cell signaling, functioning as a coenzyme.[6] commonly used in reamination reactions.

Beta-keto acids, beta-keto acids, or 3-oxides, such as acetoacetic acid, have a ketone group on the second carbon of the carboxylic acid. They are usually formed as a result of Claisen condensation.
Gamma-keto acids, gamma-keto acids or 4-oxides have a ketone group on the third carbon of the carboxylic acid. Levulinic acid is an example.

Keto acids are involved in a wide range of anabolic metabolic pathways. For example, in plants (in particular, in hemlocks, pitcher plants and parsley fool) 5-oxooctanoic acid is converted in enzymatic and non-enzymatic stages into the cyclic class alkaloids coniine.[7]

When the levels of sugars and carbohydrates consumed are low, stored fat and protein are the main source of energy. Glucogenic amino acids from proteins are converted into glucose. Ketogenic amino acids can be deaminated to form alpha-keto acids and ketones.

Alpha-keto acids are mainly used as energy for liver cells and in the synthesis of fatty acids, also in the liver.