Two steps from GDP: ribonucleotide reductase removes the 2' hydroxyl, then a kinase adds a phosphate
Route: GDP → Deoxyguanosine diphosphate → Deoxyguanosine triphosphate
Ribonucleotide reductase turns GDP into dGDP by removing the 2' hydroxyl of the ribose. Thioredoxin carries electrons from NADPH to the enzyme and ends up oxidized. The enzyme is the same one that acts on ADP, CDP and UDP. Its choice of substrate is set by the nucleoside triphosphate bound at its regulatory site, and dTTP directs it to GDP. Nucleoside diphosphate kinase then moves a phosphate from ATP to dGDP and gives dGTP. The kinase has little preference for the sugar or the base, so one enzyme finishes all four deoxy triphosphates.
Practice this pathway All pathways
| Step | Enzyme | EC | In | Out |
|---|---|---|---|---|
| 1 | Ribonucleotide reductase | 1.17.4.1 | Trx-(SH)₂ | Trx-S₂, H₂O |
| 2 | Nucleoside diphosphate kinase | 2.7.4.6 | ATP | ADP |
Enzyme names and EC numbers are those used on the interactive board. Checked against sources: see the claim table in the repository (tools/pathway_data/checks).