Kynurenine pathway

From MEpedia, a crowd-sourced encyclopedia of ME and CFS science and history
Jump to: navigation, search

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. (Jan 8, 2009). "Kynurenine Pathway Metabolites in Humans: Disease and Healthy States". International Journal of Tryptophan Research : IJTR. 2: 1–19. ISSN 1178-6469. PMC 3195227Freely accessible. PMID 22084578. 
  2. Savitz, Jonathan (Apr 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. 3.03.1 Davis, I.; Liu, A. (Jul 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. 

ME/CFS - An acronym that combines myalgic encephalomyelitis with chronic fatigue syndrome. Sometimes they are combined because people have trouble distinguishing one from the other. Sometimes they are combined because people see them as synonyms of each other.

enzyme - a substance produced by a living organism which acts as a catalyst to bring about a specific biochemical reaction.

metabolic trap hypothesis - An hypothesis which proposes that the normal metabolic functioning of the cell has become "trapped" in an abnormal state, which may lead to body-wide symptoms.

The information provided at this site is not intended to diagnose or treat any illness.
From MEpedia, a crowd-sourced encyclopedia of ME and CFS science and history.