Kynurenine pathway

From MEpedia, a crowd-sourced encyclopedia of ME and CFS science and history
Revision as of 14:55, November 30, 2019 by Notjusttired (talk | contribs) (stub)

The kynurenine pathway or tryptophan kynurenine pathway is the primary route for metabolizing the essential amino acid tryptophan in humans and other mammals[1] in order to generate cellular energy in the form of nicotinamide adenine dinucleotide (NAD+).[2][3]

If the kynurenine pathway becomes dysregulated or overactive, it can activate the immune system and result in a build-up of potentially neurotoxic compounds in the body.[3]

Function[edit | edit source]

Schematic representation of the kynurenine pathway.
Key: IDO1: indoleamine 2,3-dioxygenase 1; IDO2: indoleamine 2,3-dioxygenase 2; TDO2: tryptophan 2,3-dioxygenase; TPH1: Tryptophan hydroxylase 1; TPH2: Tryptophan hydroxylase 2; AFMID: arylformamidase; KMO: kynurenine 3-monooxygenase; CCBL1: kynurenine aminotransferase I; AADAT: kynurenine aminotransferase II; CCBL2: kynurenine aminotransferase III; KYNU: kynureninase; HAAO: 3-hydroxyanthranilate 3,4-dioxygenase; QPRT, quinolinate phosphoribosyl transferase; ACMSD: aminocarboxymuconate semialdehyde decarboxylase. Source: Favennec et al. (2016). PLoS ONE 11(6): e0158051

The kynurenine pathway

ME/CFS[edit | edit source]

The metabolic trap hypothesis suggests that a metabolic problem exists in one or more areas of a person with ME/CFS, with a defect in the IDO2 enzyme of the tryptophan kynurenine pathway being identified as a possible metabolic trap.

See also[edit | edit source]

Learn more[edit | edit source]

References[edit | edit source]

  1. Chen, Yiquan; Guillemin, Gilles J. (January 8, 2009). "Kynurenine Pathway Metabolites in Humans: Disease and Healthy States". International Journal of Tryptophan Research : IJTR. 2: 1–19. ISSN 1178-6469. PMC 3195227. PMID 22084578.
  2. Savitz, Jonathan (April 12, 2019). "The kynurenine pathway: a finger in every pie". Molecular Psychiatry: 1–17. doi:10.1038/s41380-019-0414-4. ISSN 1476-5578.
  3. 3.0 3.1 Davis, I.; Liu, A. (July 2015). "What is the tryptophan kynurenine pathway and why is it important to neurotherapeutics?". Expert review of neurotherapeutics. 15 (7): 719–721. doi:10.1586/14737175.2015.1049999. ISSN 1473-7175. PMID 26004930.
  4. Mellor, Andrew L.; Lemos, Henrique; Huang, Lei (2017). "Indoleamine 2,3-Dioxygenase and Tolerance: Where Are We Now?". Frontiers in Immunology. 8. doi:10.3389/fimmu.2017.01360. ISSN 1664-3224.