deoxyribose

Deoxyribose (2-deoxyribose) is a pentose sugar with the molecular formula C5H10O4. It is a key structural component of the DNA backbone, alternating with phosphate groups to form the sugar-phosphate backbone, while nitrogenous bases (adenine, guanine, cytosine, thymine) attach to the 1' carbon of each deoxyribose molecule. The defining feature is the absence of a hydroxyl (-OH) group at the 2' carbon (replaced by hydrogen), distinguishing it from ribose used in RNA. This lack of the 2'-OH group makes DNA more chemically stable and resistant to hydrolysis compared to RNA, which is important given DNA's role as the long-term genetic storage molecule. The 2'-OH in RNA makes it more reactive and susceptible to alkaline hydrolysis, which is why RNA is less stable and typically shorter-lived. Deoxyribose is synthesized from ribose via the enzyme ribonucleotide reductase, which reduces the 2' carbon of ribonucleotides to form deoxyribonucleotides—a critical step in DNA synthesis regulated during the cell cycle (S phase) and a target of chemotherapeutic agents (e.g., hydroxyurea inhibits ribonucleotide reductase). Understanding deoxyribose's structure is fundamental to concepts in molecular biology, including DNA replication, mutation, and the mechanism of action of various antineoplastic and antiviral drugs that target nucleotide synthesis pathways.