What is "kynurenic acid"

n. (context biochemistry English) A metabolite of tryptophan that has antiexcitotoxic and anticonvulsant activity

Kynurenic acid (KYNA or KYN) is a product of the normal metabolism of amino acid L- tryptophan. It has been shown that kynurenic acid possesses neuroactive activity. It acts as an antiexcitotoxic and anticonvulsant, most likely through acting as an antagonist at excitatory amino acid receptors. Because of this activity, it may influence important neurophysiological and neuropathological processes. As a result, kynurenic acid has been considered for use in therapy in certain neurobiological disorders. Conversely, increased levels of kynurenic acid have also been linked to certain pathological conditions.

Kynurenic acid was discovered in 1853 by the German chemist Justus von Liebig in dog urine, which it was apparently named after.

It is formed from L- kynurenine in a reaction catalyzed by the enzyme kynurenine—oxoglutarate transaminase.