Α-Ketoglutaric acid

α-Ketoglutaric acid is an organic compound with the formula H₂CC(O)(CH₂)₂CO₂H). A white, nontoxic solid, it is a common dicarboxylic acid. Relevant to its biological roles, it exists in water as its conjugate base α-ketoglutarate. It is also classified as a 2-ketocarboxylic acid. β-Ketoglutaric acid is an isomer. "Ketoglutaric acid" and "ketoglutarate", when not qualified as α or β, almost always refers respectively to α-ketoglutaric acid or α-ketoglutarate.

α-Ketoglutarate is an intermediate in the citric acid cycle, a cycle that supplies the energy to cells. It is also an intermediate in or product of several other metabolic pathways. These include its being a component of metabolic pathways that: make amino acids and in the process regulate the cellular levels of carbon, nitrogen, and ammonia; reduce the cellular levels of potentially toxic reactive oxygen species; and synthesize the neurotransmitter gamma-aminobutyric acid. It also acts as a direct stimulator of, or cofactor (i.e., required for but does not itself stimulate) for various cellular functions as defined in studies that are primarily preclinical (i.e., conducted in animal models of disease or on animal or human tissues). These studies have provided evidence that α-ketoglutarate contributes to regulating: kidney function; the benefits that resistance exercise has in reducing obesity, strengthening muscles, and preventing muscle atrophy; glucose tolerance as defined in glucose tolerance tests; aging and the development of changes that are associated with aging including old age-related disorders and diseases; the development and/or progression of certain types of cancer and inflammations; and the differentiation of immature T cells into mature T cells.