|Gene:||TDO2||Accession Number: G-11448 (MetaCyc)|
Species: Homo sapiens
A 2009 review described the subunit structure of eukaryotic tryptophan 2,3-dioxygenase as a tetramer [Rafice09]. Although the rat enzyme was reported to be a tetramer [Schutz72], the subunit structure of the human enzyme remains to be experimentally characterized. It is shown here as a monomer, to be updated when experimental data are available.
Despite this lack of subunit structure characterization, the reaction mechanism of the recombinant human enzyme expressed in Escherichia coli has been studied in detail using kinetic, spectroscopic and redox analyses [Basran08, Batabyal07].
In mammals this enzyme is present mostly in liver and is also found in skin. It is regulated by glucocorticoid hormones and its physiological substrate L-tryptophan. In other tissues, indoleamine 2,3-dioxygenase catalyzes the conversion of L-tryptophan to N-formylkynurenine (in [Batabyal07]). Catalytic differences between these two enzymes have been shown [Basran08]. Reviewed in [Rafice09].
Gene Citations: [Comings95]
|Map Position: [156,824,847 -> 156,841,550]|
Molecular Weight of Polypeptide: 47.872 kD (from nucleotide sequence)
Unification Links: ArrayExpress:P48775 , Entrez-gene:6999 , Mint:MINT-1446261 , PhosphoSite:P48775 , Pride:P48775 , Protein Model Portal:P48775 , SMR:P48775 , String:9606.ENSP00000281525 , UniProt:P48775
Enzymatic reaction of: tryptophan 2,3-dioxygenase
EC Number: 18.104.22.168
The reaction direction shown, that is, A + B ↔ C + D versus C + D ↔ A + B, is in accordance with the direction in which it was curated.
The reaction is physiologically favored in the direction shown.
In Pathways: L-tryptophan degradation III (eukaryotic) , L-tryptophan degradation XI (mammalian, via kynurenine) , NAD biosynthesis II (from tryptophan) , L-tryptophan degradation to 2-amino-3-carboxymuconate semialdehyde
Basran08: Basran J, Rafice SA, Chauhan N, Efimov I, Cheesman MR, Ghamsari L, Raven EL (2008). "A kinetic, spectroscopic, and redox study of human tryptophan 2,3-dioxygenase." Biochemistry 47(16);4752-60. PMID: 18370401
Comings95: Comings DE, Muhleman D, Dietz G, Sherman M, Forest GL (1995). "Sequence of human tryptophan 2,3-dioxygenase (TDO2): presence of a glucocorticoid response-like element composed of a GTT repeat and an intronic CCCCT repeat." Genomics 29(2);390-6. PMID: 8666386
Rafice09: Rafice SA, Chauhan N, Efimov I, Basran J, Raven EL (2009). "Oxidation of L-tryptophan in biology: a comparison between tryptophan 2,3-dioxygenase and indoleamine 2,3-dioxygenase." Biochem Soc Trans 37(Pt 2);408-12. PMID: 19290871
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