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.
Defects in the encoded protein can result in inosine triphosphate pyrophosphorylase deficiency. [6] The enzyme ITPase dephosphorylates ribavirin triphosphate in vitro to ribavirin monophosphate, and ITPase reduced enzymatic activity present in 30 % of humans potentiates mutagenesis in hepatitis C virus. [9] Gene variants predicting reduced predicted ITPase activity have been associated with decreased risk of ribavirin-induced anemia, increased risk of thrombocytopenia, lower ribavirin concentrations, as well as a ribavirin-like reduced relapse risk following interferon-based therapy for hepatitis C virus (HCV) genotype 2 or 3 infection. [10]
Nucleotides are organic molecules consisting of a nucleoside and a phosphate. They serve as monomeric units of the nucleic acid polymers – deoxyribonucleic acid (DNA) and ribonucleic acid (RNA), both of which are essential biomolecules within all life-forms on Earth. Nucleotides are obtained in the diet and are also synthesized from common nutrients by the liver.
Ribavirin, also known as tribavirin, is an antiviral medication used to treat RSV infection, hepatitis C and some viral hemorrhagic fevers. For hepatitis C, it is used in combination with other medications such as simeprevir, sofosbuvir, peginterferon alfa-2b or peginterferon alfa-2a. Among the viral hemorrhagic fevers it is used for Lassa fever, Crimean–Congo hemorrhagic fever, and Hantavirus infection but should not be used for Ebola or Marburg infections. Ribavirin is taken by mouth or inhaled.
A salvage pathway is a pathway in which a biological product is produced from intermediates in the degradative pathway of its own or a similar substance. The term often refers to nucleotide salvage in particular, in which nucleotides are synthesized from intermediates in their degradative pathway.
A nucleotide triphosphate is a molecule containing a nitrogenous base bound to a 5-carbon sugar, with three phosphate groups bound to the sugar. It is an example of a nucleotide. They are the molecular precursors of both DNA and RNA, which are chains of nucleotides made through the processes of DNA replication and transcription. Nucleoside triphosphates also serve as a source of energy for cellular reactions and are involved in signalling pathways.
Inosinic acid or inosine monophosphate (IMP) is a nucleotide. Widely used as a flavor enhancer, it is typically obtained from chicken byproducts or other meat industry waste. Inosinic acid is important in metabolism. It is the ribonucleotide of hypoxanthine and the first nucleotide formed during the synthesis of purine nucleotides. It can also be formed by the deamination of adenosine monophosphate by AMP deaminase. It can be hydrolysed to inosine.
Chromosome 20 is one of the 23 pairs of chromosomes in humans. Chromosome 20 spans around 63 million base pairs and represents between 2 and 2.5 percent of the total DNA in cells. Chromosome 20 was fully sequenced in 2001 and was reported to contain over 59 million base pairs. Since then, due to sequencing improvements and fixes, the length of chromosome 20 has been updated to just over 63 million base pairs.
Purine nucleoside phosphorylase, PNP, PNPase or inosine phosphorylase is an enzyme that in humans is encoded by the NP gene. It catalyzes the chemical reaction
Purine metabolism refers to the metabolic pathways to synthesize and break down purines that are present in many organisms.
Equilibrative nucleoside transporter 1 (ENT1) is a protein that in humans is encoded by the SLC29A1 gene. Multiple alternatively spliced variants, encoding the same protein, have been found for this gene. Expressed on red blood cell surfaces, these variants make up the Augustine blood group system.
In enzymology, a nucleoside-diphosphatase (EC 3.6.1.6) is an enzyme that catalyzes the chemical reaction
In enzymology, a nucleoside-triphosphate diphosphatase (EC 3.6.1.19) is an enzyme that catalyzes the chemical reaction
Ectonucleotide pyrophosphatase/phosphodiesterase family member 1 is an enzyme that in humans is encoded by the ENPP1 gene.
Cytosolic 5'-nucleotidase 3 (NTC53), also known as cytosolic 5'-nucleotidase 3A, pyrimidine 5’-nucleotidase, and p56, is an enzyme that in humans is encoded by the NT5C3, or NT5C3A, gene on chromosome 7.
dCTP pyrophosphatase 1 is an enzyme that in humans is encoded by the DCTPP1 gene.
Bis(5'-nucleosyl)-tetraphosphatase [asymmetrical] is an enzyme that in humans is encoded by the NUDT2 gene.
Ectonucleoside triphosphate diphosphohydrolase 2 is an enzyme that in humans is encoded by the ENTPD2 gene.
Adenylate kinase 2 is an enzyme that is encoded in humans by the AK2 gene. The AK2 protein is found in the intermembrane space of the mitochondrion.
5', 3'-nucleotidase, cytosolic, also known as 5'(3')-deoxyribonucleotidase, cytosolic type (cdN) or deoxy-5'-nucleotidase 1 (dNT-1), is an enzyme that in humans is encoded by the NT5C gene on chromosome 17.
Inosine-5'-monophosphate dehydrogenase 2, also known as IMP dehydrogenase 2, is an enzyme that in humans is encoded by the IMPDH2 gene.
2-hydroxy-dATP diphosphatase is an enzyme that in humans is encoded by the NUDT1 gene. During DNA repair, the enzyme hydrolyses oxidized purines and prevents their addition onto the DNA chain. As such it has important role in aging and cancer development.
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