Inosine triphosphate pyrophosphatase is an enzyme that in humans is encoded by the ITPAgene, by the rdgBgene in bacteria E.coli and the HAM1gene in yeast S. cerevisiae. 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.
The protein encoded by this gene hydrolyzes inosine triphosphate and deoxyinosine triphosphate to the monophosphate nucleotide and diphosphate. The enzyme possesses a multiple substrate-specificity and acts on other nucleotides including xanthosine triphosphate and deoxyxanthosine triphosphate. The encoded protein, which is a member of the HAM1 NTPase protein family, is found in the cytoplasm and acts as a homodimer.
^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. PMID11278832.
Clawson GA, Song YL, Schwartz AM, et al. (1992). "Interaction of human immunodeficiency virus type I Rev protein with nuclear scaffold nucleoside triphosphatase activity". Cell Growth Differ. 2 (11): 575–82. PMID1667585.
Deloukas P, Matthews LH, Ashurst J, et al. (2002). "The DNA sequence and comparative analysis of human chromosome 20". Nature. 414 (6866): 865–71. doi:10.1038/414865a. PMID11780052.
Marinaki AM, Duley JA, Arenas M, et al. (2005). "Mutation in the ITPA gene predicts intolerance to azathioprine". Nucleosides Nucleotides Nucleic Acids. 23 (8–9): 1393–7. doi:10.1081/NCN-200027639. PMID15571265.
Marinaki AM, Sumi S, Arenas M, et al. (2005). "Allele frequency of inosine triphosphate pyrophosphatase gene polymorphisms in a Japanese population". Nucleosides Nucleotides Nucleic Acids. 23 (8–9): 1399–401. doi:10.1081/NCN-200027641. PMID15571266.
Maeda T, Sumi S, Ueta A, et al. (2005). "Genetic basis of inosine triphosphate pyrophosphohydrolase deficiency in the Japanese population". Mol. Genet. Metab. 85 (4): 271–9. doi:10.1016/j.ymgme.2005.03.011. PMID15946879.
Breen DP, Marinaki AM, Arenas M, Hayes PC (2005). "Pharmacogenetic association with adverse drug reactions to azathioprine immunosuppressive therapy following liver transplantation". Liver Transpl. 11 (7): 826–33. doi:10.1002/lt.20377. PMID15973722.
Arenas M, Duley J, Sumi S, et al. (2007). "The ITPA c.94C>A and g.IVS2+21A>C sequence variants contribute to missplicing of the ITPA gene". Biochim. Biophys. Acta. 1772 (1): 96–102. doi:10.1016/j.bbadis.2006.10.006. PMID17113761.
Stenmark P, Kursula P, Flodin S, et al. (2007). "Crystal structure of human inosine triphosphatase. Substrate binding and implication of the inosine triphosphatase deficiency mutation P32T". J. Biol. Chem. 282 (5): 3182–7. doi:10.1074/jbc.M609838200. PMID17138556.
Atanasova S, Shipkova M, Svinarov D, et al. (2007). "Analysis of ITPA phenotype-genotype correlation in the Bulgarian population revealed a novel gene variant in exon 6". Therapeutic drug monitoring. 29 (1): 6–10. doi:10.1097/FTD.0b013e3180308554. PMID17304144.