Indole3pyruvic

Indole-3-pyruvic acid, also called indole-3-pyruvate, is an organic compound featuring an indole ring linked to a pyruvate-like side chain. It is commonly described as an indole-substituted α-keto acid derived from tryptophan.

In plants, IPA is a central intermediate in the biosynthesis of the plant hormone indole-3-acetic acid (IAA). It is produced from tryptophan by tryptophan aminotransferases of the TAR/TAA family, which transfer the amino group to α-ketoglutarate to form IPA and glutamate. IPA is then converted to indole-3-acetaldehyde by flavin-containing monooxygenases of the YUCCA family, and subsequently oxidized to IAA by aldehyde oxidases. This IPA-to-IAA sequence is a key route for auxin production in many plant species.

In microorganisms, IPA can be formed during tryptophan catabolism and can feed into pathways that generate various indole derivatives, including IAA in some plant-associated bacteria. IPA or its derivatives have been detected across bacteria and fungi under conditions of tryptophan metabolism; in many cases, IPA serves as an intermediate that contributes to diverse indole metabolite production.

Because of its role as a biosynthetic intermediate, IPA is studied in plant physiology, biochemistry, and microbiology to understand auxin production and regulation, as well as tryptophan metabolism more broadly. In research contexts, exogenous IPA is sometimes used to probe auxin biosynthesis pathways and signaling responses.