The nature of the inhibition of Ehrlich tumor cell ribonucleotide reducÃ-ase by combinations of agents directed at the nonheme iron-containing component and the effector-binding com ponent was studied with the use of isobolograms. From these studies, it was determined that the combinations of pyrazoloimidazole (IMPY) and dialdehyde of inosine, IMPY and deoxyguanosine triphosphate (dGTP), IMPY a...

Mammals experience some degree of hypoxia during their lifetime. In response to hypoxic challenge, mammalian cells orchestrate specific responses at transcriptional and posttranslational level which lead changes in the purine metabolites order cope with threatening conditions. The aim this study was evaluate enzymes involved metabolism human muscle Muscle culture were exposed enzymatic activity...

The nature of the inhibition of Ehrlich tumor cell ribonucleotide reductase by combinations of agents directed at the non-heme iron-containing component and the effector-binding component was studied with the use of isobolograms. From these studies, it was determined that the combinations of pyrazoloimidazole (IMPY) and dialdehyde of inosine, IMPY and deoxyguanosine triphosphate (dGTP), IMPY an...

Cellular nucleotide pools are often contaminated by base analog nucleotides which interfere with a plethora of biological reactions, from DNA and RNA synthesis to cellular signaling. An evolutionarily conserved inosine triphosphate pyrophosphatase (ITPA) removes the non-canonical purine (d)NTPs inosine triphosphate and xanthosine triphosphate by hydrolyzing them into their monophosphate form an...

A nucleoside kinase has been purified about 1680-fold from L1210 leukemia cells with deoxyadenosine as the phosphate acceptor and with adenosine triphosphate as phosphate donor. The molecular weight of the enzyme, determined by Sephadex G-200 column chromatography, was found to be about 100,000. Purified enzyme, after the final step of purification and also after disc gel electrophoresis (Rf 0....

objective: the itpa gene is responsible to remove free deaminated purine nucleotides of itp, ditp and xtp from nucleotide pool of the cells. it seems that dysfunction in its activity, not only can increas the base substitution mutations frequency but also can works as a contrived factor to creating instability in genetic materials of the cells. there are several reports about the existence of s...

In a previous communication (l), an accumulation of oxaloacetic acid was implicated as the cause of a decline of succinate oxidation in liver mitochondria from rats fed a diet deficient in vitamin E. This conclusion appeared justified from observations that compounds known to accelerate the removal of oxalo.acetate would relieve this decline of succinate oxidation. There was, however, a lack of...

objective: one of the most significant damages to the genetic material is oxidative deamination of dna and free nucleotides in the cell pool. incorporation of deaminated purine nucleotides such as inosine triphosphate (itp, ditp) into the dna can increase the frequency of base substitution mutation. it has been suggested that presence and accumulation of these rough nucleotides can lead to gene...

The metabolism and intracellular compartmentalization of adenine nucleotides in a preparation of adult rat heart myocytes showing good morphology, viability, and tolerance to calcium ion has been examined by high performance liquid chromatography. These myocytes contain an average of 23 nmol adenine nucleotide per milligram protein which is about 60% of the adenine nucleotide content of intact ...

Inosine triphosphate pyrophosphatase (ITPA), a key enzyme involved in maintaining the purity of cellular nucleoside triphosphate pools, specifically recognizes inosine triphosphate and xanthosine triphosphate (including the deoxyribose forms) and detoxifies them by catalyzing the hydrolysis of a phosphoanhydride bond, releasing pyrophosphate. This prevents their inappropriate use as substrates ...