The specific activity of ribonucleotide reductase was found to increase significantly after deoxyribonucleic acid inhibition in seven species of bacteria investigated. This group of bacteria includes species with B12-dependent ribonucleotide reductase as well as some with an Escherichia coli-type ribonucleotide reductase.

Ribonucleotide reductase activity is required for generating deoxyribonucleotides for DNA replication. Schizosaccharomyces pombe cells lacking ribonucleotide reductase activity arrest during S phase of the cell cycle. In a screen for hydroxyurea-sensitive mutants in S. pombe, we have identified a gene, liz1(+), which when mutated reveals an additional, previously undescribed role for ribonucleo...

The levels of ribonucleotide reductase, DNA polymerase, thymidine kinase, and labeled thymidine incorporation into DNA were measured in Ehrlich ascites tumor cells as a function of time after inoculation of the tumor in mice. The levels of ribonucleotide reductase and thymidine kinase activities decreased with tumor growth, while the level of DNA polymerase activity did not decrease. Thymidine ...

Ribonucleotide reductase is an iron-containing enzyme that is essential for DNA synthesis. Whereas previous studies have used various iron chelators to examine the relationship between cellular iron metabolism and ribonucleotide reductase activity in cells, they have not elucidated the relationship between iron transport into cells and the expression of the gene for ribonucleotide reductase. To...

BACKGROUND The present study aims to investigate the subunit expression and enzyme activity of ribonucleotide reductase in cervical cancer patients, and detect the combined effect of the ribonucleotide reductase inhibitor gemcitabine and the chemotherapeutic agent carboplatin on cervical cancer cell lines. METHODS Using quantitative reverse transcription polymerase chain reaction, Western blo...

suppresses DNAsynthesis by inhibition of ribonucleotide reductase.4) Ribonucleotide reductase plays an essential role in DNAsynthesis in most organisms.5) The enzyme is a nonheme iron-containing protein, which requires ATPand Mg2+ as co factors. As previously reported that IC202C has art affinity against Fe(III) ion,3) we have examined the effect of IC202C on ribonucleotide reductase activity u...

This reaction in vitro requires the combined function of three pure Escherichia coli proteins, namely the Bl and B2 subunits of ribonucleotide reductase and glutaredoxin. The stoichiometry was demonstrated by determinations of the products r3H]dCDP and GSSG. The standard assay couples oxidation of NADPH to the reduction of GSSG by glutathione reductase. The apparent K,,, value of glutaredoxin w...

In both clam oocytes and sea urchin eggs, fertilization triggers the synthesis of a set of proteins specified by stored maternal mRNAs. One of the most abundant of these (p41) has a molecular weight of 41,000. This paper describes the identification of p41 as the small subunit of ribonucleotide reductase, the enzyme that provides the precursors necessary for DNA synthesis. This identification i...

In nearly all systems studied, ribonucleotide reductase consists of two non-identical subunits. We present here the results of our study on herpes simplex virus (HSV) ribonucleotide reductase in favour of the existence of two subunits, H1 and H2, different from the mammalian subunits, M1 and M2. First, although the viral subunits could not be separated by Blue Sepharose chromatography (unlike m...