Center for Bioinformatics
Oxidoreductases | Transferases | Hydrolases | Lyases | Isomerases | Ligases

Basic Information

Enzyme Number

Official Name

indoleamine 2,3-dioxygenase

Name from literature

Indoleamine 2,3-dioxygenase

Pathway from literature

the kynurenine pathway of tryptophan metabolism/UV filter biosynthesis

Pathway from KEGG

Amino Acid Metabolism; Tryptophan metabolism; map00380


Human (9606)

Genome localization

8p12-p11[3620 ], 8p11.21[169355 ],


A protohemoprotein. Requires ascorbic acid and methylene blue for activity. This enzyme has broader substrate specificity than EC, tryptophan 2,3-dioxygenase [1]. It is induced in response to pathological conditions and host-defense mechanisms and its distribution in mammals is not confined to the liver [2]. While the enzyme is more active with D-tryptophan than L-tryptophan, its only known function to date is in the metabolism of L-tryptophan [2,6]. Superoxide radicals can replace O2 as oxygen donor [4,7].

Rate-limiting Description

"This reaction is the first and the rate-limiting step in the kynurenine pathway, the major Trp catabolic pathway in mammals." (16511306)

"To identify whether binding of NF-kappaB upstream of the IRF-1 gene is rate-limiting in IRF-1 expression in response to IFN-gamma and TNF-alpha, a proteasome inhibitor was utilized to maintain nuclear translocation of NF-kappaB at constitutive levels; its effect on IRF-1 expression and IDO-specific transcription was evaluated." (16931033)

Gene ontology

Gene ontology

GO:0019674 (P) NAD metabolic process [P14902 ];
GO:0020037 (F) heme binding [P14902 ];
GO:0005829 (C) cytosol [P14902 ];
GO:0005506 (F) iron ion binding [P14902 ];
GO:0007565 (P) female pregnancy [P14902 ];
GO:0009055 (F) electron carrier activity [P14902 ];
GO:0055114 (P) oxidation reduction [P14902 ];
GO:0004833 (F) tryptophan 2, 3-dioxygenase activity [P14902 ];
GO:0033754 (F) indoleamine 2, 3-dioxygenase activity [P14902 ];




Entrez Gene

169355; 3620


14113; 00935

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  Last Modified: 2009-03-24  
  Design by Zhao Min