conclusions in patients with chc g1 and receiving combination therapy, itpa snp-based index was an accurate and practical solution for prediction of severe anemia. background single-nucleotide polymorphisms (snp) in the inosine triphosphate pyrophosphatase (itpa) gene correlate with ribavirin (rbv)-induced anemia in patients with chronic hepatitis c (chc) receiving combination therapy. managing...

Inosine triphosphate pyrophosphatases, which are ubiquitous house-cleaning enzymes, hydrolyze noncanonical nucleoside triphosphates (inosine triphosphate (ITP) and xanthosine triphosphate (XTP)) and prevent the incorporation of hypoxanthine or xanthine into nascent DNA or RNA. Here we present the 1.5-A-resolution crystal structure of the inosine triphosphate pyrophosphatase RdgB from Escherichi...

The rabbit reticulocyte is capable of utilizing purines and their ribosyl derivatives for nucleoside triphosphate formation. Adenine, adenosine, hypoxanthine, and inosine are used extensively for the synthesis of adenosine triphosphate. Xanthine, guanine, and guanosine are utilized primarily for the synthesis of guanosine triphosphate. The inhibitor 6-diazo-S-oxo-L-norleucine inhibits the utili...

Inosine triphosphatase (ITPase) is the enzyme that catalyzes the conversion of inosine triphosphate (ITP) and deoxy-inosine triphosphate (dITP) to inosine monophosphate and deoxy-inosine monophosphate, respectively, thereby maintaining low intracellular concentrations of ITP and dITP. Individuals deficient in ITPase activity were first recognized over 30 years ago. For decades, no clinical sign...

Plant viruses typically have highly condensed genomes, yet the plant-pathogenic Cassava brown streak virus, Ugandan cassava and Euphorbia ringspot virus are unusual in encoding an enzyme not found any other “house-cleaning” inosine triphosphatase. Inosine triphosphatases (ITPases) conserved enzymes that occur all kingdoms of life perform a house-cleaning function by hydrolysing noncanonical nuc...

Nucleotides function in a variety of biological reactions; however, they can undergo various chemical modifications. Such modified nucleotides may be toxic to cells if not eliminated from the nucleotide pools. We performed a screen for modified-nucleotide binding proteins and identified human nucleoside diphosphate linked moiety X-type motif 16 (NUDT16) protein as an inosine triphosphate (ITP)/...

The method described here allows the quantitative simultaneous determination of adenosine 5'-triphosphate, adenosine 5'-diphosphate, adenosine 5'-monophosphate, adenosine, guanosine 5'-triphosphate, guanosine 5'-diphosphate, guanosine, inosine 5'-monophosphate, inosine, uric acid, xanthine, hypoxanthine and beta-nicotinamide adenine dinucleotide by ion-pair high performance liquid chromatograph...

Since the isolation of Bacillus anthracis exotoxins in the 1960s, the detrimental activity of edema factor (EF) was considered as adenylyl cyclase activity only. Yet the catalytic site of EF was recently shown to accomplish cyclization of cytidine 5'-triphosphate, uridine 5'-triphosphate and inosine 5'-triphosphate, in addition to adenosine 5'-triphosphate. This review discusses the broad EF su...

In a number of isolated blood vessel types, hypoxia causes an acute contraction that is dependent on the presence of nitric oxide and activation of soluble guanylyl cyclase. It is more pronounced when the preparations are constricted and is therefore termed hypoxic augmentation of vasoconstriction. This hypoxic response is accompanied by increases in the intracellular level of inosine 5'-tripho...

ITP and dITP exist in all cells. dITP is potentially mutagenic, and the levels of these nucleotides are controlled by inosine triphosphate pyrophosphatase (EC ). Here we report the cloning, expression, and characterization of a 21.5-kDa human inosine triphosphate pyrophosphatase (hITPase), an enzyme whose activity has been reported in many animal tissues and studied in populations but whose pro...