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| Names | |
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| Preferred IUPAC name (2S)-2-Amino-4-(2-aminophenyl)-4-oxo-butanoic acid | |
| Other names (S)-Kynurenine | |
| Identifiers | |
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3D model (JSmol) | |
| ChEBI | |
| ChEMBL | |
| ChemSpider | |
| DrugBank | |
| MeSH | Kynurenine |
PubChem CID | |
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CompTox Dashboard (EPA) | |
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| Properties | |
| C10H12N2O3 | |
| Molar mass | 208.217 g·mol−1 |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). | |
l-Kynurenine is a metabolite of the amino acid l-tryptophan used in the production of niacin.
Contents
Kynurenine is synthesized by the enzyme tryptophan dioxygenase, which is made primarily but not exclusively in the liver, and indoleamine 2,3-dioxygenase, which is made in many tissues in response to immune activation. [1] An important source is the intestine. [2] Kynurenine and its further breakdown products carry out diverse biological functions, including dilating blood vessels during inflammation [3] and regulating the immune response. [4] Some cancers increase kynurenine production, which increases tumor growth. [1] [5]
Kynurenine protects the eye by absorbing UV light, especially in the UVA region (315–400 nm). [6] Kynurenine is present in the lens and retina as one of multiple tryptophan derivatives produced in the eye, including 3-hydroxykynurenine, that together provide UV protection and aid in enhancing visual acuity. [7] [8] The use of kynurenine as a UV filter is consistent with its photostability and low photosensitization, owing to its efficient relaxation from the UV-induced excited state. [9] The concentration of this UV filter decreases with age, [10] and this loss of free kynurenine and the concomitant formation of relatively more photosensitizing kynurenine derivatives and kynurenine-protein conjugates may contribute to the formation of cataracts. [11] [12] [13]
Evidence suggests that increased kynurenine production may precipitate depressive symptoms associated with interferon treatment for hepatitis C. [14] Cognitive deficits in schizophrenia are associated with imbalances in the enzymes that break down kynurenine. [15] Blood levels of kynurenine are reduced in people with bipolar disorder. [16] Kynurenine production is increased in Alzheimer's disease [17] [18] and cardiovascular disease [19] where its metabolites are associated with cognitive deficits [20] and depressive symptoms. [21] Kynurenine is also associated with tics. [22] [23] Myokines regulate it's metabolism. [24] [25] [26]
Kynureninase catalyzes the conversion of kynurenine into anthranilic acid [27] while kynurenine-oxoglutarate transaminase catalyzes its conversion into kynurenic acid. Kynurenine 3-hydroxylase catalyzes the conversion of kynurenine to 3-hydroxykynurenine. [28]
Kynurenine has also been identified as one of two compounds that makes up the pigment that gives the goldenrod crab spider its yellow color. [29]
