Figure 4: The oxidative or kynurenine pathway up to quinolinic acid and down to acetyl CoA. Adapted from Figure 1 in ref [6] (A. A.-B. Badawy. Kynurenine pathway of tryptophan metabolism: regulatory and functional aspects. Int J Tryptophan Res. 10, 1-20, 2017 doi: 10.1177/1178646917691938. Abbreviations used are: ACMS (2-Amino-3-carboxymuconic acid-6-semialdehyde), AMS (2-Aminomuconic acid -6-semialdehyde), IDO (indoleamine 2,3-dioxygenase), TDO (tryptophan 2,3-dioxygenase).