Which drug inhibits ribonucleotide reductase?
Hydroxyurea, a ribonucleotide reductase inhibitor, is a well-tolerated oral cytotoxic agent that can control blood cell counts rapidly in most patients with CML.
Does 5 fluorouracil inhibit ribonucleotide reductase?
Abstract. 5-Fluorouracil (5-FU) is one of the most well established chemotherapeutic agents in the treatment of esophageal cancer. Ribonucleotide reductase M1 (RRM-1) is the rate‑limiting enzyme in de novo DNA synthesis, and has been considered to play an important role in the 5-FU metabolic pathway.
Is 5-fluorouracil an antimetabolite?
1. Primary and secondary resistance to the widely used antimetabolite 5-fluorouracil (5-FU) are common phenomena in cancer chemotherapy. Because 5-FU still remains the agent of choice in the treatment of, for example, colorectal cancer, circumvention of resistance is of vital importance. 2.
Where is ribonucleotide reductase found?
We interpret our results to mean that in mammalian cells ribonucleotide reduction takes place in the cytoplasm and from there the deoxyribonucleotides are transported into the nucleus to serve in DNA synthesis.
Is MTX an antimetabolite?
Methotrexate (MTX) is an antimetabolite drug that inhibits the enzyme dihydrofolate reductase, thereby preventing the conversion of folic acid into tetrahydrofolate, and inhibiting DNA synthesis in the S-phase of the cell cycle (Newton, 2006a).
What kind of enzyme is ribonucleotide reductase?
Ribonucleotide reductase (RNR) is a key enzyme that mediates the synthesis of deoxyribonucleotides, the DNA precursors, for DNA synthesis in every living cell. This enzyme converts ribonucleotides to deoxyribonucleotides, the building blocks for DNA replication, and repair.
Which of the following is a substrate of ribonucleotide reductase?
The substrates for RNR are ADP, GDP, CDP and UDP. dTDP (deoxythymidine diphosphate) is synthesized by another enzyme (thymidylate kinase) from dTMP (deoxythymidine monophosphate).
Does dATP inhibit ribonucleotide reductase?
Low concentrations of dATP stimulate reduction of pyrimidine ribonucleoside diphosphates, whereas at high concentrations, dATP becomes a potent, general inhibitor of nucleotide reduction; it is also seen that low concentrations of dATP counteract the stimulatory effects of dTTP and dGTP.
What is the role of ribonucleotide reductase in DNA synthesis?
The iron -dependent enzyme, ribonucleotide reductase (RNR), is essential for DNA synthesis. Class I RNR enzymes are constructed from large RNR1 and small RNR2 subunits which associate to form an active heterodimeric tetramer.
Are class IE ribonucleotides capable of ribonucleotide reduction activity?
Together, these observations suggest that class Ie RNRs are capable of ribonucleotide reduction activity despite the significant changes to the predicted metal-binding motif.
What is the name of the enzyme that converts ribonucleotides?
Ribonucleotide reductase. Jump to navigation Jump to search. Ribonucleotide reductase (RNR), also known as ribonucleotide diphosphate reductase (rNDP), is an enzyme that catalyzes the formation of deoxyribonucleotides from ribonucleotides.
What is ribonucleotide reductase (RNR)?
Jump to navigation Jump to search. Ribonucleotide reductase (RNR), also known as ribonucleoside diphosphate reductase (rNDP), is an enzyme that catalyzes the formation of deoxyribonucleotides from ribonucleotides. It catalyzes this formation by removing the 2′-hydroxyl group of the ribose ring of nucleoside diphosphates.