Alpha-keto acids Also known as alpha-ketoacids and
2-oxoacids, these compounds have the keto group adjacent to the carboxylic acid. They often arise by
oxidative deamination of
amino acids, and reciprocally, they are
precursors to the same. Alpha-keto acids possesses extensive chemistry as
acylation agents. Furthermore, alpha-keto acids such as
phenylpyruvic acid are endogenous sources for
carbon monoxide (as a
gasotransmitter) and pharmaceutical
prodrug scaffold. Important representatives: •
pyruvic acid, pervasive intermediate in metabolism. •
oxaloacetic acid, a component of the
Krebs cycle. •
alpha-ketoglutaric acid, a 5-carbon ketoacid derived from
glutamic acid. Alpha-ketoglutarate participates in
cell signaling by functioning as a
coenzyme. It is commonly used in
transamination reactions. •
2-Oxoadipic acid Alpha keto acids are used primarily as energy for liver cells and in
fatty acid synthesis, also in the liver.
Beta-keto acids Beta-keto acids (beta-ketoacids, or 3-oxoacids) have the ketone group at the second carbon from the carboxylic acid. They generally form by the
Claisen condensation. The presence of the keto group at the beta position allows them to easily undergo thermal
decarboxylation. •
Acetoacetic acid is the parent of this series.
Other keto acids Gamma-keto acids (Gamma-ketoacids, or 4-oxoacids) have the ketone group at the third carbon from the carboxylic acid.
Levulinic acid is an example. 5-Ooxo-octanoic acid is converted in enzymatic and non-enzymatic steps into the
cyclic class of
coniine alkaloids. Keto acids appear in a wide variety of anabolic pathways in metabolism. For instance, in plants (specifically, in
hemlock,
pitcher plants, and
fool's parsley). ==See also==