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unreviewed

Ribonucleotide reductase (RNR)

1 reactions · 1 pathways

Clinical / pharmacological. Target of hydroxyurea; allosterically controlled by dNTPs

What it does, reaction by reaction

1 reactions

Pyrimidine De Novo Synthesis (through to UMP, then CTP/dTMP) Nucleotide Metabolism · Cytosol (one mitochondrial step)

step 10 Irreversible/directional

UDP → dUDP (route to dUMP)

Converts UDP into dUDP

› Notes

Ribonucleotide reductase (RNR) catalyzes UDP + reducing equivalents → dUDP + oxidized electron-transfer proteins. In humans the reducing equivalents are supplied principally by NADPH through thioredoxin reductase and thioredoxin (or through glutaredoxin/glutathione); RNR is covered mechanistically in the deoxyribonucleotide section.

Showing all 1 reactions.

What accelerates and inhibits it

Regulation is pathway-specific, so each context is listed separately

1 entries

Deoxyribonucleotide Formation (Ribonucleotide Reductase pathway and thymidylate synthesis)

Accelerated by

ATP at the activity site; substrate specificity is directed by ATP/dATP, dTTP, and dGTP at the specificity site

Inhibited by

dATP at the activity site (global feedback inhibition); hydroxyurea quenches the radical; iron limitation impairs radical-center assembly

Hormonal control

Transcription and activity rise in late G1/S through E2F and proliferative growth-factor signaling; p53-induced RRM2B supports DNA repair under stress.

Recent literature

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Europe PMC · fetched just now · sorted by publication date

  1. 1
    Mechanistic studies on HNRNPA2B1 suggest binding but not selective recognition of m<sup>6</sup>A.

    Park R, Demny M, Miller LG, Pedraza C, Xenophontos X, Hunt RK, Orr AA, Perez LM, Montalbano M, Contreras LM, … · 2026-03-02

    cited 1× open access unreviewed
  2. 2
    Targeting IMPDH to inhibit SAMHD1 in <i>KMT2A</i>-rearranged leukaemia.

    Klootsema Y, Tsesmetzis N, Sharma S, Hofmann S, Thier J, Dirks C, Hormann FM, Yagüe-Capilla M, Bohlin A, Beng… · 2025-12-15

    open access unreviewed
  3. 3
    PAF1c depletion confers chemoresistance to topoisomerase inhibitors.

    Li D, Zhu C, Wang T, Chen Q, Chen Q. · 2026-05-22

    open access unreviewed
  4. 4
    Mechanisms of Hydroxyurea-Mediated DNA Damage Potentiation in Fanconi Anemia Cells.

    Bustamante B, Sosa D, Melendez-Zajgla J, López-Velázquez G, Ostrosky-Wegman P, Rodriguez A, Torres L, Juárez-… · 2026-07-29

    unreviewed
  5. 5
    Ensemble Docking and Molecular Dynamics Indicate Dynamic Modulation of hnRNPA1 UP1 Interdomain Behavior by Natural Products.

    Lourembam RM, Raj N, Sharma GS, Sarangthem ID, Sharma NH, Thorat SS. · 2026-07-02

    unreviewed
  6. 6
    Subtype-specific clinical significance of RRM1 and RRM2 expression in non-small cell lung cancer: a TCGA-based analysis.

    Yun SY, Lee Y, Lee J, Hong H, Lee JH. · 2026-07-07

    unreviewed
  7. 7
    HuR-HuB autoregulatory network governs inflammatory factors expression.

    Fu X, Lu Y, Kong L, Qi Y, Zhong X, Ba X, Ke Y. · 2026-05-20

    open access unreviewed
  8. 8
    Crosstalk of thioredoxin system and programmed cell death: from pathophysiology to novel therapy.

    Wu Y, Su Y, Pan F, Jin F, Huang H, Deng A, Lu Y, Lu Y, Li T, Du J, Tong X, Li Y. · 2026-05-12

    open access unreviewed
  9. 9
    Adaptive Regulation of dNTP Homeostasis Confers Osimertinib Resistance in EGFR-Mutant Non-Small Cell Lung Carcinoma.

    Xie Q, Wang Y, Fernandez A, Lei Y, Gong Y, Hess JD, Yang L, Xin D, Williams TM, Zheng L, Shen B, Li M. · 2026-07-01

    open access unreviewed
  10. 10
    Ribonucleotide reductase M1 regulates the cell cycle via minichromosome maintenance proteins.

    Malysa A, Kreahling JM, Freeman SN, Bao B, Zhao J, Zhang X, Ratnam M, Bepler G. · 2025-11-08

    open access unreviewed

External claims. These come from an index outside this database and are not checked against it. Treat them as leads.