. "Deoxyribonucleotides needed for DNA repair are synthesized de novo by the reduction of ribonucleoside 5'-diphosphates. This reaction is catalyzed by a nuclear form of ribonucleotide reductase active throughout the cell cycle. The reducing equivalents needed for these reactions can be provided directly by thioredoxin."^^ . . . . . "NDP + reduced thioredoxin => dNDP + oxidized thioredoxin + H2O"^^ . "Reduction of nuclear ribonucleoside 5'-diphosphates to deoxyribonucleoside 5'-diphosphates (thioredoxin)"^^ . "1.17.4.1"^^ . . . . . . . . .