Source:http://linkedlifedata.com/resource/umls/id/C0297817
NCI: Ribonucleoside-Diphosphate Reductase M2 Chain, encoded by the RRM2 gene, is a subunit of ribonucleoside-diphosphate reductase, a heterodimeric cytoplasmic enzyme essential in dividing cells that reduces ribonucleotides to deoxyribonucleotide precursors for DNA synthesis in S phase. Enzyme activity closely correlates with the cellular rate of growth and appears to vary with the cell cycle. A substrate specificity site and a catalytic activity site regulate enzyme activity. A substrate-binding catalytic site on M1 is only formed in the presence of M2. Synthesis of M2 is regulated in a cell-cycle dependent fashion. Wild-type p53 regulates human ribonucleotide reductase by protein-protein interaction with p53R2 as well as M2 subunits. RRM2 gene amplification from a homogeneous staining chromosome region and altered transcription regulation is associated with drug resistance. (From LocusLink and NCI)