3-Hydroxyanthranilate 3,4-dioxygenase (HAAO (3HAO))

3-Hydroxyanthranilate 3,4-dioxygenase is a non-heme iron(II)-dependent enzyme essential for the oxidative ring cleavage of 3-hydroxyanthranilic acid in the kynurenine pathway, resulting in the production of quinolinic acid, a precursor for NAD⁺ biosynthesis that also functions as a neurotoxin via NMDA receptor activation. The protein is expressed mainly in peripheral organs (liver, kidney), but also at lower levels in the CNS. Its activity and regulation influence the pathophysiology of several neurological, inflammatory, and oncologic diseases, making it an emerging target for therapeutic and biomarker strategies. Dysfunction or altered expression can disturb tryptophan metabolism, contribute to cancer progression, immune escape, and development of neurotoxic states or mood disorders.

Other names

3HAOHAAO3-hydroxyanthranilate oxygenase3-hydroxyanthranilic acid oxygenase3-hydroxyanthranilic oxygenase3-hydroxyanthranilic acid oxidase3-hydroxyanthranilate:oxygen 3,4-oxidoreductase (decyclizing)

Drug intervention would primarily involve enzyme inhibition to reduce quinolinic acid levels and downstream toxic effects in neural tissue or tumor environment; inhibition may impact NAD⁺ synthesis