Ribonucleotide reductase (RNR, class Ia)
Clinical / pharmacological. Target of hydroxyurea; allosterically controlled by dNTPs
What it does, reaction by reaction
Deoxyribonucleotide Formation (Ribonucleotide Reductase pathway and thymidylate synthesis) Nucleotide Metabolism · Cytosol
Nucleoside diphosphates → deoxyribonucleoside diphosphates
Converts ADP GDP CDP UDP into dADP dGDP dCDP dUDP
› Notes
Class Ia RNR catalyzes ADP, GDP, CDP, or UDP + reducing equivalents → dADP, dGDP, dCDP, or dUDP + oxidized electron-transfer proteins. The human enzyme is an alpha2beta2 complex: the RRM2/RRM2B small subunit uses a diiron center to generate a stable tyrosyl radical, and the RRM1 large subunit contains catalytic cysteines that reduce the 2′-hydroxyl group. Reducing equivalents are transferred from NADPH through thioredoxin reductase and reduced thioredoxin (or through NADPH, glutathione reductase, glutathione, and glutaredoxin); the chemical reduction of each NDP requires one NADPH-derived pair of electrons. This is the rate-limiting and committed step for de novo deoxyribonucleotide production.
Showing all 1 reactions.
What accelerates and inhibits it
Regulation is pathway-specific, so each context is listed separately
No regulation recorded for this enzyme in the source documents.
Recent literature
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