Record Information
Version1.0
StatusDetected and Quantified
Creation Date2021-11-19 04:29:24 UTC
Update Date2024-04-30 19:56:59 UTC
Metabolite IDMMDBc0032971
Metabolite Identification
Common NameL-Kynurenine
DescriptionL-Kynurenine, which is also known as Kynurenine or 3-Anthraniloylalanine, belongs to the class of compounds known as alkyl-phenylketones. Alkyl-phenylketones are aromatic compounds containing a ketone substituted by one alkyl group, and a phenyl group.  Kynurenine is a metabolite of the amino acid L-tryptophan and is used in the production of niacin. Specifically, kynurenine is synthesized by the enzyme tryptophan dioxygenase, which is made primarily but not exclusively in the liver. Kynurenine is also synthesized by indoleamine 2,3-dioxygenase (IDO), which is found in many tissues and is often overexpressed in response to immune activation. Kynurenine and its other tryptophan breakdown products (Trp catabolites) carry out a wide range of biological functions, including dilating blood vessels during inflammation (PMID: 20190767 ) and regulating the immune response (PMID: 21041655 ). Kynurenine is the precursor to the neuroprotective agent known as kynurenic acid. Kynurenine is also the precursor to the neurotoxic agent quinolinic acid. Dysregulation in the balance between these two kynurenine derivatives can be observable in many disorders such as stroke, epilepsy, multiple sclerosis, and amyotrophic lateral sclerosis. Blood levels of kynurenine are reduced in people with bipolar disorder (PMID: 33077852 ) and schizophrenia (PMID: 21727251 ). On the other hand, kynurenine production is increased in Alzheimer's disease (PMID: 16008823 ). and cardiovascular disease (PMID: 12814390 ), where its metabolites are associated with cognitive deficits (PMID: 20639188 ) and depressive symptoms. Kynurenine and its precursor (tryptophan) also play important roles in regulating inflammation and the immune responses to infectious organisms. Reduced levels of tryptophan in the blood are typically seen when individuals are fighting chronic infections, suffering from traumatic injuries (burns or wounds) or experiencing sepsis (PMID: 26309411 ). Tryptophan is mainly catabolized to kynurenine by the enzyme known as indoleamine-2,3-dioxygenase (IDO) which is induced by interferon gamma (IFN-gamma or IFNG). Kynurenine activates the aryl hydrocarbon receptor (AhR), which plays a key role immune suppression. The role of IDO is to effectively deplete tryptophan levels to starve infectious organisms (bacteria and parasites), thereby killing them or slowing their growth.  On the other hand, the AhR activation by kynurenine leads to a state of immunosuppression and is intended to serve as a brake on the immune response to the infectious organisms (overexpression of IFNG and IL-1B).  Unfortunately, tryptophan starvation is often not effective against viruses or even all infectious microbes. As a result, this AhR activation by kynurenine can lead to a situation where viruses (or certain pathogens) continue to survive and multiply even while the immune system is effectively turning off. As a result, high levels of kynurenine and low levels of tryptophan (a high kynurenine to tryptophan or KT ratio) can lead to or even be symptomatic of chronic viral or pathogenic infections or, at worse, sepsis and septic shock (PMID: 33338598 ; PMID: 21731667 ). Kynurenine and its metabolites are also known as uremic toxins (PMID: 12092667 ). Chronically high levels of uremic toxins are known to cause damage to kidneys, liver, heart and the brain. Serum albumin binds to most uremic toxins quite strongly and can act as a first line of defense against transient rises in these compounds.
Structure
Synonyms
ValueSource
(2S)-2-Amino-4-(2-aminophenyl)-4-oxobutanoic acidChEBI
3-Anthraniloyl-L-alanineChEBI
KYNURENINEChEBI
(2S)-2-Amino-4-(2-aminophenyl)-4-oxobutanoateGenerator
(S)-alpha,2-Diamino-3-hydroxy-gamma-oxo-benzenebutanoateHMDB
(S)-alpha,2-Diamino-3-hydroxy-gamma-oxo-benzenebutanoic acidHMDB
3-Anthraniloyl-alanineHMDB
3-AnthraniloylalanineHMDB
alpha,2-Diamino-gamma-oxo-benzenebutanoateHMDB
alpha,2-Diamino-gamma-oxo-benzenebutanoic acidHMDB
DL-KynurenineHMDB
KynureninHMDB
QuinurenineHMDB
L-KynurenineHMDB
3-(2-aminobenzoyl)-L-alanineHMDB
KYNAHMDB
Molecular FormulaC10H12N2O3
Average Mass208.2139
Monoisotopic Mass208.08479226
IUPAC Name(2S)-2-amino-4-(2-aminophenyl)-4-oxobutanoic acid
Traditional NameL-kynurenine
CAS Registry Number343-65-7
SMILES
N[C@@H](CC(=O)C1=CC=CC=C1N)C(O)=O
InChI Identifier
InChI=1S/C10H12N2O3/c11-7-4-2-1-3-6(7)9(13)5-8(12)10(14)15/h1-4,8H,5,11-12H2,(H,14,15)/t8-/m0/s1
InChI KeyYGPSJZOEDVAXAB-QMMMGPOBSA-N