這個基因編碼核糖核苷酸還原酶的大的催化亞單位，這是一種將核糖核苷酸轉化為脫氧核糖核苷酸所必需的酶。在細胞周期的S階段以及多個DNA修復過程中，可用的脫氧核糖核苷酸池對DNA復制很重要。選擇性剪接導致多個轉錄變體。
This gene encodes the large and catalytic subunit of ribonucleotide reductase, an enzyme essential for the conversion of ribonucleotides into deoxyribonucleotides. A pool of available deoxyribonucleotides is important for DNA replication during S phase of the cell cycle as well as multiple DNA repair processes. Alternative splicing results in multiple transcript variants.