Rinonucleotide Reductase is Regulated by a Complex Feedback Network.
the synthesis of the four dNTP in the amounts required for DNA synthesis is accomplished through feedback control. the proper intracellular ratios of dNTPs is essential for normal growth. a deficiency of any the is lethal, whereas an excess is mutagenic because probability that a given dNTP will be erroneously incorporated into a growing DNA strand increases with its concentration relative to those of the other dNTPs. The activities of both E. coli and mammalian ribonucleotide reduc- tases are remarkably responsive to the levels of nucleotides in the cell.