Briefly, through a series of enzymatic steps, tryptophan is normally converted into kynurenine, then to 3-hydroxykynurenine via kynurenine 3-monooxygenase (KMO; B2, NAD[P.sup.+]), then 3-hydroxyanthranilic acid is formed by kynureninase (KYNU; B6), and proceeds down the pathway to become either acetyl-coA, picolinic acid or quinolinic acid, which is further converted into NA[D.sup.+] through another series of enzymatic steps.
Kynurenine 3-monooxygenase https://www.uniprot.org/uniprot/015229 Accessed 26 July 2018.
 reported that kynurenine 3-monooxygenase
(KMO), an enzyme playing a critical role in Huntington's and Alzheimer's diseases, exhibits tumor-promoting effects towards HCC.
Sathyasaikumar et al., "Kynurenine 3-monooxygenase
inhibition in blood ameliorates neurodegeneration," Cell, vol.
Rescue of white egg 1 mutant by introduction of the wild-type Bombyx kynurenine 3-monooxygenase
L-KYN is considered to be the end product of KYN pathway metabolism in most extrahepatic cells, whereas macrophages produce the largest amount of quinolinic acid (QUIN) in accordance with the highest activities of kynurenine 3-monooxygenase
(KMO) and kynureninase [4, 68].
Giorgini, "Targeting kynurenine 3-monooxygenase
(kmo): implications for therapy in Huntington's disease," CNS & Neurological Disorders, vol.