Kynurenine

• ( S)- kynurenine
• (R ) - kynurenine
• ( RS)- kynurenine
• (S )-3- Anthraniloylalanin
• (R )-3- Anthraniloylalanin
• (RS )-3- Anthraniloylalanin
• 2 -amino-3 -(2- aminobenzoyl ) - propionic acid
• IUPAC: 2-amino- 4-(2 -aminophenyl) - 4-oxo- butanoic acid

• 2922-83-0 [( S)- kynurenine ]
• 343-65-7 [( RS)- kynurenine ]

Colorless leaflets

Fixed

Slightly soluble in water, forming water-soluble salts with acids

Template: Infobox chemical / molecular formula search available

Kynurenine (Greek kyon dog and ouron urine) is an aromatic non-proteinogenic amino acid. There are two stereoisomers of Kynurenins: ( S)- kynurenine [ Synonym: L- kynurenine ] and (R) - kynurenine [ Synonym: D- kynurenine ]. Kynurenine gets increasingly medical interest as a precursor of the NMDA receptor antagonist kynurenic acid. Only the (S) - or L- form shows biological activity.

History and habitat

( S)- kynurenine is a Stoffwechselintermediat in the degradation of tryptophan in many living things. It was first found in urine (Latin urina ) of dogs (Greek kyon ), of which the name of the compound is derived. Adolf Butenandt examined in his inaugural dissertation in 1940 and together with the geneticist Alfred Kühn the influence of kynurenine, the first one held for a hormone in the eye pigmentation of insects. In a vitamin B6 deficiency, the amount of excreted kynurenine is increased in the urine.

(Bio) synthesis

Racemic kynurenine can technically be obtained in several steps in good yield from o- chloroaniline.

The synthesis of L- kynurenine in animals is performed using the enzyme Arylformamidase that catalyzes the hydrolytic cleavage of formic acid from N- formylkynurenine.

Properties

L- kynurenine as the monohydrate forms colorless, plate-like crystals which dissolve in little water, but good in acids. Oxidative deamination is formed during heating of L- kynurenine to kynurenic acid cyclic, which is the actual NMDA receptor antagonist.

Biological Significance

L- kynurenine is a Stoffwechselintermediat in many living organisms, in the degradation of the amino acid tryptophan as well as in the biosynthesis of nicotinic acid and NAD.

As a metabolite of tryptophan in the body L- kynurenine is excreted daily in amounts of from about 1 mg in the urine.

Increased levels of L - kynurenine in the brain by the application of L- Kynureninsulfat shown neuroprotective effects in neurodegenerative diseases in animal models.

In the urine of female masu salmon (Oncorhynchus masou ) affects L- kynurenine as a pheromone.

The oxidation product of 3-hydroxy- L- kynurenine is also an intermediate in the formation of Ommochromen (Eye pigments ) of crabs and insects.