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Aliases for IDO2 Gene

Aliases for IDO2 Gene

  • Indoleamine 2,3-Dioxygenase 2 2 3 5
  • Indoleamine-Pyrrole 2,3-Dioxygenase-Like Protein 1 3 4
  • Indoleamine-Pyrrole 2,3 Dioxygenase-Like 1 2 3
  • Indoleamine 2,3-Dioxygenase-Like Protein 1 3 4
  • INDOL1 3 4
  • IDO-2 3 4
  • Indoleamine 2,3-Dioxygenase-Like 1 Protein 3
  • EC 1.13.11.- 4

External Ids for IDO2 Gene

Previous HGNC Symbols for IDO2 Gene

  • INDOL1

Previous GeneCards Identifiers for IDO2 Gene

  • GC08P039913
  • GC08P039792
  • GC08P038325

Summaries for IDO2 Gene

Entrez Gene Summary for IDO2 Gene

  • Along with the enzymes encoded by the INDO (MIM 147435) and TDO2 (MIM 191070) genes, the enzyme encoded by the INDOL1 gene metabolizes tryptophan in the kynurenine pathway (Ball et al., 2007 [PubMed 17499941]).[supplied by OMIM, Feb 2011]

GeneCards Summary for IDO2 Gene

IDO2 (Indoleamine 2,3-Dioxygenase 2) is a Protein Coding gene. Among its related pathways are Histidine, lysine, phenylalanine, tyrosine, proline and tryptophan catabolism and Tryptophan metabolism. GO annotations related to this gene include heme binding and indoleamine 2,3-dioxygenase activity. An important paralog of this gene is IDO1.

UniProtKB/Swiss-Prot for IDO2 Gene

  • Catalyzes the first and rate limiting step of the catabolism of the essential amino acid tryptophan along the kynurenine pathway (PubMed:17671174). Involved in immune regulation. May not play a significant role in tryptophan-related tumoral resistance (PubMed:25691885).

No data available for Tocris Summary , Gene Wiki entry , PharmGKB "VIP" Summary , fRNAdb sequence ontologies and piRNA Summary for IDO2 Gene

Genomics for IDO2 Gene

Regulatory Elements for IDO2 Gene

Enhancers for IDO2 Gene
GeneHancer Identifier Score Enhancer Sources TSS distance (kb) Number of Genes Away Size (kb) Transcription Factor Binding Sites within enhancer Other Gene Targets for Enhancer

Enhancers around IDO2 on UCSC Golden Path with GeneCards custom track

Genomic Location for IDO2 Gene

39,934,614 bp from pter
40,016,391 bp from pter
81,778 bases
Plus strand

Genomic View for IDO2 Gene

Genes around IDO2 on UCSC Golden Path with GeneCards custom track

Cytogenetic band:
IDO2 Gene in genomic location: bands according to Ensembl, locations according to GeneLoc (and/or Entrez Gene and/or Ensembl if different)
Genomic Location for IDO2 Gene
GeneLoc Logo Genomic Neighborhood Exon StructureGene Density

RefSeq DNA sequence for IDO2 Gene

Proteins for IDO2 Gene

  • Protein details for IDO2 Gene (UniProtKB/Swiss-Prot)

    Protein Symbol:
    Recommended name:
    Indoleamine 2,3-dioxygenase 2
    Protein Accession:
    Secondary Accessions:
    • A4UD41
    • F5H5G0

    Protein attributes for IDO2 Gene

    420 amino acids
    Molecular mass:
    47075 Da
    Name=heme; Xref=ChEBI:CHEBI:30413;
    Quaternary structure:
    No Data Available
    • IDO1 and IDO2 are 2 distinct enzymes which catalyze the same reaction. IDO2 affinity for tryptophan is much lower than that of IDO1. 50 % of Caucasians harbor polymorphisms which abolish IDO2 enzymatic activity. IDO2 is expressed in human tumors in an inactive form: tryptophan degradation is entirely provided by IDO1 in these cells (PubMed:18418598). IDO2 may play a role as a negative regulator of IDO1 by competing for heme-binding with IDO1 (PubMed:25394548). Low efficiency IDO2 enzymes have been conserved throughout vertebrate evolution, whereas higher efficiency IDO1 enzymes are dispensable in many lower vertebrate lineages (PubMed:25950090). IDO1 may have arisen by gene duplication of a more ancient proto-IDO gene before the divergence of marsupial and eutherian (placental) mammals.

    Alternative splice isoforms for IDO2 Gene


neXtProt entry for IDO2 Gene

Proteomics data for IDO2 Gene at MOPED

Post-translational modifications for IDO2 Gene

  • Modification sites at PhosphoSitePlus
  • Modification sites at neXtProt

Other Protein References for IDO2 Gene

ENSEMBL proteins:
REFSEQ proteins:

No data available for DME Specific Peptides for IDO2 Gene

Domains & Families for IDO2 Gene

Protein Domains for IDO2 Gene


Suggested Antigen Peptide Sequences for IDO2 Gene

GenScript: Design optimal peptide antigens:

Graphical View of Domain Structure for InterPro Entry



  • Belongs to the indoleamine 2,3-dioxygenase family.
  • Belongs to the indoleamine 2,3-dioxygenase family.
genes like me logo Genes that share domains with IDO2: view

No data available for Gene Families for IDO2 Gene

Function for IDO2 Gene

Molecular function for IDO2 Gene

UniProtKB/Swiss-Prot CatalyticActivity:
L-tryptophan + O(2) = N-formyl-L-kynurenine.
UniProtKB/Swiss-Prot EnzymeRegulation:
Activity is inhibited by D-1MT (1-methyl-D-tryptophan) and MTH-trp (methylthiohydantoin-DL-tryptophan) but not L-1MT (1-methyl-L-tryptophan).
UniProtKB/Swiss-Prot Function:
Catalyzes the first and rate limiting step of the catabolism of the essential amino acid tryptophan along the kynurenine pathway (PubMed:17671174). Involved in immune regulation. May not play a significant role in tryptophan-related tumoral resistance (PubMed:25691885).

Enzyme Numbers (IUBMB) for IDO2 Gene

Gene Ontology (GO) - Molecular Function for IDO2 Gene

GO ID Qualified GO term Evidence PubMed IDs
GO:0004833 tryptophan 2,3-dioxygenase activity EXP 17671174
genes like me logo Genes that share ontologies with IDO2: view
genes like me logo Genes that share phenotypes with IDO2: view

Animal Models for IDO2 Gene

MGI Knock Outs for IDO2:

Animal Model Products

miRNA for IDO2 Gene

No data available for Human Phenotype Ontology , Transcription Factor Targets and HOMER Transcription for IDO2 Gene

Localization for IDO2 Gene

Subcellular locations from

Jensen Localization Image for IDO2 Gene COMPARTMENTS Subcellular localization image for IDO2 gene
Compartment Confidence
cytosol 4

No data available for Subcellular locations from UniProtKB/Swiss-Prot and Gene Ontology (GO) - Cellular Components for IDO2 Gene

Pathways & Interactions for IDO2 Gene

genes like me logo Genes that share pathways with IDO2: view

UniProtKB/Swiss-Prot Q6ZQW0-I23O2_HUMAN

  • Pathway: Amino-acid degradation; L-tryptophan degradation via kynurenine pathway; L-kynurenine from L-tryptophan: step 1/2.

Interacting Proteins for IDO2 Gene

Gene Ontology (GO) - Biological Process for IDO2 Gene

GO ID Qualified GO term Evidence PubMed IDs
GO:0006569 tryptophan catabolic process TAS --
GO:0019441 tryptophan catabolic process to kynurenine ISS 17499941
GO:0044281 small molecule metabolic process TAS --
genes like me logo Genes that share ontologies with IDO2: view

No data available for SIGNOR curated interactions for IDO2 Gene

Drugs & Compounds for IDO2 Gene

(9) Drugs for IDO2 Gene - From: ApexBio and HMDB

Name Status Disease Links Group Role Mechanism of Action Clinical Trials
L-Tryptophan Approved Nutra Positive, Allosteric regulator 0
Melatonin Approved Nutra Antagonist Melatonin receptors MT inhibitor 239
Oxitriptan Approved Nutra Inhibition, Inhibitor 0
INCB024360 Pharma Potent IDO1 inhibitor, 3-dioxygenase (INDO) inhibitor, 3-dioxygenase (INDO) inhibitor, indoleamine 2 0
Indoximod (NLG-8189) Pharma Indoleamine 2,3-dioxygenase (IDO) pathway inhibitor Potent and selective HDAC6 inhibitor 0

(5) Additional Compounds for IDO2 Gene - From: HMDB

Name Synonyms Role CAS Number PubChem IDs PubMed IDs
  • AFMK
  • Formyl-N-acetyl-5-methoxykynurenamine
  • N-Acetyl-N-formyl-5-methoxykynurenamine
  • N-[3-(2-Formamido-5-methoxy-phenyl)-3-oxo-propyl]acetamide
  • 3-(N-Formylanthraniloyl)-Alanine
  • alpha-Amino-2-(formylamino)-gamma-oxo-Benzenebutanoate
  • alpha-Amino-2-(formylamino)-gamma-oxo-Benzenebutanoic acid
  • Formylkynurenine
  • N'-Formyl-Kynurenine
  • Dioxygen
  • Molecular oxygen
  • O2
  • Oxygen
  • Oxygen molecule

(3) ApexBio Compounds for IDO2 Gene

Compound Action Cas Number
INCB024360 Potent IDO1 inhibitor 914471-09-3
Indoximod (NLG-8189) Indoleamine 2,3-dioxygenase (IDO) pathway inhibitor Potent and selective HDAC6 inhibitor 110117-83-4
NLG919 Potent IDO pathway inhibitor 1402836-58-1
genes like me logo Genes that share compounds with IDO2: view

Transcripts for IDO2 Gene

mRNA/cDNA for IDO2 Gene

(1) REFSEQ mRNAs :
(5) Additional mRNA sequences :
(9) Selected AceView cDNA sequences:
(4) Ensembl transcripts including schematic representations, and UCSC links where relevant :

Unigene Clusters for IDO2 Gene

Indoleamine 2,3-dioxygenase 2:
Representative Sequences:

Alternative Splicing Database (ASD) splice patterns (SP) for IDO2 Gene

No ASD Table

Relevant External Links for IDO2 Gene

GeneLoc Exon Structure for
ECgene alternative splicing isoforms for

Expression for IDO2 Gene

mRNA expression in normal human tissues for IDO2 Gene

mRNA differential expression in normal tissues according to GTEx for IDO2 Gene

This gene is overexpressed in Liver (x28.7), Thyroid (x7.7), and Testis (x6.3).

Integrated Proteomics: protein expression in normal tissues and cell lines from ProteomicsDB, PaxDb, and MOPED for IDO2 Gene

SOURCE GeneReport for Unigene cluster for IDO2 Gene Hs.676257

mRNA Expression by UniProt/SwissProt for IDO2 Gene

Tissue specificity: Detected in liver, small intestine, spleen, placenta, thymus, lung, brain, kidney, and colon (PubMed:17671174). Also expressed at low level in testis and thyroid. Not expressed in the majority of human tumor samples (>99%) (PubMed:25691885).
genes like me logo Genes that share expression patterns with IDO2: view

Protein tissue co-expression partners for IDO2 Gene

Primer Products

No data available for mRNA expression in embryonic tissues and stem cells from LifeMap Discovery and Protein differential expression in normal tissues for IDO2 Gene

Orthologs for IDO2 Gene

This gene was present in the common ancestor of animals and fungi.

Orthologs for IDO2 Gene

Organism Taxonomy Gene Similarity Type Details
(Bos Taurus)
Mammalia IDO2 35
  • 79.85 (n)
  • 75.68 (a)
IDO2 36
  • 76 (a)
(Canis familiaris)
Mammalia IDO2 35
  • 83.91 (n)
  • 79.46 (a)
IDO2 36
  • 79 (a)
(Mus musculus)
Mammalia Ido2 35
  • 76.78 (n)
  • 73.38 (a)
Ido2 16
Ido2 36
  • 72 (a)
(Pan troglodytes)
Mammalia IDO2 35
  • 99.01 (n)
  • 98.64 (a)
IDO2 36
  • 96 (a)
(Rattus norvegicus)
Mammalia Ido2 35
  • 78.45 (n)
  • 76.18 (a)
(Monodelphis domestica)
Mammalia IDO2 36
  • 73 (a)
(Ornithorhynchus anatinus)
Mammalia IDO2 36
  • 68 (a)
(Gallus gallus)
Aves INDOL1 35
  • 64.43 (n)
  • 60.05 (a)
IDO2 36
  • 60 (a)
(Anolis carolinensis)
Reptilia IDO2 36
  • 55 (a)
tropical clawed frog
(Silurana tropicalis)
Amphibia ido1 35
  • 57.88 (n)
  • 53.52 (a)
African clawed frog
(Xenopus laevis)
Amphibia Xl.1465 35
(Danio rerio)
Actinopterygii ido1 35
  • 59.01 (n)
  • 51.28 (a)
ido1 36
  • 46 (a)
baker's yeast
(Saccharomyces cerevisiae)
Saccharomycetes BNA2 36
  • 29 (a)
Species with no ortholog for IDO2:
  • A. gosspyii yeast (Ashbya gossypii)
  • Actinobacteria (Mycobacterium tuberculosis)
  • African malaria mosquito (Anopheles gambiae)
  • Alicante grape (Vitis vinifera)
  • alpha proteobacteria (Wolbachia pipientis)
  • amoeba (Dictyostelium discoideum)
  • Archea (Pyrococcus horikoshii)
  • barley (Hordeum vulgare)
  • beta proteobacteria (Neisseria meningitidis)
  • bread mold (Neurospora crassa)
  • Chromalveolata (Phytophthora infestans)
  • common water flea (Daphnia pulex)
  • corn (Zea mays)
  • E. coli (Escherichia coli)
  • filamentous fungi (Aspergillus nidulans)
  • Firmicute bacteria (Streptococcus pneumoniae)
  • fission yeast (Schizosaccharomyces pombe)
  • fruit fly (Drosophila melanogaster)
  • green algae (Chlamydomonas reinhardtii)
  • honey bee (Apis mellifera)
  • K. lactis yeast (Kluyveromyces lactis)
  • loblloly pine (Pinus taeda)
  • malaria parasite (Plasmodium falciparum)
  • medicago trunc (Medicago Truncatula)
  • moss (Physcomitrella patens)
  • orangutan (Pongo pygmaeus)
  • pig (Sus scrofa)
  • rainbow trout (Oncorhynchus mykiss)
  • rice (Oryza sativa)
  • rice blast fungus (Magnaporthe grisea)
  • schistosome parasite (Schistosoma mansoni)
  • sea anemone (Nematostella vectensis)
  • sea squirt (Ciona intestinalis)
  • sea squirt (Ciona savignyi)
  • sea urchin (Strongylocentrotus purpuratus)
  • sorghum (Sorghum bicolor)
  • soybean (Glycine max)
  • stem rust fungus (Puccinia graminis)
  • sugarcane (Saccharum officinarum)
  • thale cress (Arabidopsis thaliana)
  • tomato (Lycopersicon esculentum)
  • toxoplasmosis (Toxoplasma gondii)
  • Trichoplax (Trichoplax adhaerens)
  • wheat (Triticum aestivum)
  • worm (Caenorhabditis elegans)

Evolution for IDO2 Gene

Gene Tree for IDO2 (if available)
Gene Tree for IDO2 (if available)

Paralogs for IDO2 Gene

Paralogs for IDO2 Gene

(1) SIMAP similar genes for IDO2 Gene using alignment to 3 proteins:

genes like me logo Genes that share paralogs with IDO2: view

Variants for IDO2 Gene

Polymorphic Variants from UniProtKB/Swiss-Prot for IDO2 Gene

The variant Trp-248 (p.R248W) drastically reduces the enzymatic activity (PubMed:17671174, PubMed:18418598). The Del359-420 variant (p.Y359X) generates a truncated, enzymatically inactive protein (PubMed:17671174). The high prevalence of these polymorphic alleles results in a non-functional IDO2 enzyme in up to 50% of Caucasians (PubMed:18418598).

Sequence variations from dbSNP and Humsavar for IDO2 Gene

SNP ID Clin Chr 08 pos Sequence Context AA Info Type
rs10109853 - 40,005,362(+) GCATC(C/T)GGATC reference, missense
rs2032723 -- 39,995,442(+) cgccc(A/G)gataa intron-variant
rs2052377 -- 39,965,331(-) TTTTT(C/G)TATTT intron-variant
rs2052378 -- 39,965,119(-) CAATG(C/T)TGTGC intron-variant
rs2052379 -- 39,965,111(-) TGCTA(A/G)GAGGA intron-variant

Structural Variations from Database of Genomic Variants (DGV) for IDO2 Gene

Variant ID Type Subtype PubMed ID
esv2736908 CNV Deletion 23290073
esv2663657 CNV Deletion 23128226
esv1987205 CNV Deletion 18987734
esv2677111 CNV Deletion 23128226

Variation tolerance for IDO2 Gene

Gene Damage Index Score: 23.62; 99.57% of all genes are more intolerant (likely to be disease-causing)

No data available for Relevant External Links for IDO2 Gene

Disorders for IDO2 Gene

Relevant External Links for IDO2

Genetic Association Database (GAD)
Human Genome Epidemiology (HuGE) Navigator
Atlas of Genetics and Cytogenetics in Oncology and Haematology:

No disorders were found for IDO2 Gene.

No data available for MalaCards , UniProtKB/Swiss-Prot and Genatlas for IDO2 Gene

Publications for IDO2 Gene

  1. Heme-binding-mediated negative regulation of the tryptophan metabolic enzyme indoleamine 2,3-dioxygenase 1 (IDO1) by IDO2. (PMID: 25394548) Lee Y.K. … Choi E.Y. (Exp. Mol. Med. 2014) 3 4 67
  2. The human indoleamine 2,3-dioxygenase gene and related human genes. (PMID: 17430106) Murray M.F. (Curr. Drug Metab. 2007) 3 23
  3. The SOCS3-independent expression of IDO2 supports the homeostatic generation of T regulatory cells by human dendritic cells. (PMID: 24391212) Trabanelli S. … Lemoli R.M. (J. Immunol. 2014) 3
  4. An atlas of genetic influences on human blood metabolites. (PMID: 24816252) Shin S.Y. … Soranzo N. (Nat. Genet. 2014) 3
  5. The Fe-heme structure of met-indoleamine 2,3-dioxygenase-2 determined by X-ray absorption fine structure. (PMID: 24858687) Aitken J.B. … Lay P.A. (Biochem. Biophys. Res. Commun. 2014) 3

Products for IDO2 Gene

Sources for IDO2 Gene