這個基因編碼核糖核苷酸還原酶的兩個不相同亞單位之一。這種還原酶催化核糖核苷酸形成脫氧核糖核苷酸。編碼蛋白（m2）的合成以細胞周期依賴性方式調節。該基因的轉錄可以從替代啟動子啟動，這導致兩種亞型的長度不同的N末端。在1號染色體和X號染色體上發現了相關的假基因。
This gene encodes one of two non-identical subunits for ribonucleotide reductase. This reductase catalyzes the formation of deoxyribonucleotides from ribonucleotides. Synthesis of the encoded protein (M2) is regulated in a cell-cycle dependent fashion. Transcription from this gene can initiate from alternative promoters, which results in two isoforms that differ in the lengths of their N-termini. Related pseudogenes have been identified on chromosomes 1 and X.