sugarribose

Sugarribose, commonly called ribose sugar, is a five-carbon sugar (pentose) that forms the backbone of RNA. It is an aldopentose with the chemical formula C5H10O5 and a molecular weight of 150.13 g/mol. It exists as D- and L- enantiomers; biology uses the D- form (D-ribose).

In aqueous solution, ribose cyclizes to form cyclic hemiacetals; the predominant cyclic form is beta-D-ribofuranose (a five-membered ring). A less common pyranose form also exists. In nucleotides, the ribose is linked to a nucleobase at the 1' carbon, and to phosphate groups at other positions to form the backbone. The 2' hydroxyl (2'-OH) distinguishes ribose from deoxyribose (which lacks the 2'-OH found in DNA).

Biosynthesis and function: Ribose is produced in cells primarily via the pentose phosphate pathway, generating ribose-5-phosphate, a precursor for nucleotide and cofactor synthesis. It is a component of RNA, ATP, NAD+, and many other biomolecules in the ribose form. D-ribose is also sold as a dietary supplement, though clinical evidence for energy or athletic performance benefits remains mixed.

Natural occurrence: Ribose occurs in all living organisms; it can be obtained from dietary sources and synthesized endogenously as needed for nucleotide production. It is a reducing sugar due to the open-chain aldehyde form in equilibrium, though the cyclic forms predominate.