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Protein ITPA PDB 2car.png
Available structures
PDBOrtholog search: PDBe RCSB
AliasesITPA, C20orf37, HLC14-06-P, dJ794I6.3, My049, ITPase, NTPase, inosine triphosphatase
External IDsMGI: 96622 HomoloGene: 6289 GeneCards: ITPA
Gene location (Human)
Chromosome 20 (human)
Chr.Chromosome 20 (human)[1]
Chromosome 20 (human)
Genomic location for ITPA
Genomic location for ITPA
Band20p13Start3,208,868 bp[1]
End3,223,870 bp[1]
RNA expression pattern
PBB GE ITPA 209171 at fs.png
More reference expression data
RefSeq (mRNA)


RefSeq (protein)


Location (UCSC)Chr 20: 3.21 – 3.22 MbChr 2: 130.67 – 130.68 Mb
PubMed search[3][4]
View/Edit HumanView/Edit Mouse

Inosine triphosphate pyrophosphatase is an enzyme that in humans is encoded by the ITPA gene,[5][6] by the rdgB gene in bacteria E.coli[7] and the HAM1 gene in yeast S. cerevisiae.[8] Two transcript variants encoding two different isoforms have been found for this gene. Also, at least two other transcript variants have been identified which are probably regulatory rather than protein-coding.[citation needed]


The protein encoded by this gene hydrolyzes inosine triphosphate and deoxyinosine triphosphate to the monophosphate nucleotide and diphosphate.[6] The enzyme possesses a multiple substrate-specificity and acts on other nucleotides including xanthosine triphosphate and deoxyxanthosine triphosphate.[8] The encoded protein, which is a member of the HAM1 NTPase protein family, is found in the cytoplasm and acts as a homodimer.

Clinical significance[edit]

Defects in the encoded protein can result in inosine triphosphate pyrophosphorylase deficiency.[6]


  1. ^ a b c GRCh38: Ensembl release 89: ENSG00000125877 - Ensembl, May 2017
  2. ^ a b c GRCm38: Ensembl release 89: ENSMUSG00000074797 - Ensembl, May 2017
  3. ^ "Human PubMed Reference:".
  4. ^ "Mouse PubMed Reference:".
  5. ^ Lin S, McLennan AG, Ying K, Wang Z, Gu S, Jin H, Wu C, Liu W, Yuan Y, Tang R, Xie Y, Mao Y (May 2001). "Cloning, expression, and characterization of a human inosine triphosphate pyrophosphatase encoded by the itpa gene". J Biol Chem. 276 (22): 18695–701. doi:10.1074/jbc.M011084200. PMID 11278832.
  6. ^ a b c "Entrez Gene: ITPA inosine triphosphatase (nucleoside triphosphate pyrophosphatase)".
  7. ^ Burgis NE, Cunningham RP (2007). "Substrate specificity of RdgB protein, a deoxyribonucleoside triphosphate pyrophosphohydrolase". J Biol Chem. 282 (8): 3531–8. doi:10.1074/jbc.M608708200. PMID 17090528.
  8. ^ a b Davies O, Mendes P, Smallbone K, Malys N (2012). "Characterisation of multiple substrate-specific (d)ITP/(d)XTPase and modelling of deaminated purine nucleotide metabolism". BMB Reports. 45 (4): 259–64. doi:10.5483/BMBRep.2012.45.4.259. PMID 22531138.

Further reading[edit]