ribotides

Ribotides are nucleotides that contain ribose as their sugar, as opposed to deoxyribose in deoxyribonucleotides. In many contexts the term is used interchangeably with ribonucleotides and refers to nucleotides that form RNA and participate in energy transfer and signaling within cells. A ribotide consists of a nitrogenous base (adenine, cytosine, guanine, or uracil) linked to a ribose sugar, which is further esterified by one to three phosphate groups at the 5' position.

The most common forms are ribonucleoside monophosphates (AMP, CMP, GMP, UMP), ribonucleoside diphosphates (ADP, GDP, etc.), and ribonucleoside triphosphates (ATP, GTP, CTP, UTP). These compounds serve as the building blocks of RNA and also as essential energy carriers and cofactors. For example, ATP and GTP provide energy and phosphate groups for numerous cellular processes, while cyclic nucleotides derived from ribotides act as signaling molecules in various pathways.

Biosynthesis of ribotides occurs through de novo pathways that build nucleotides from simpler precursors, starting with ribose-5-phosphate and the ribose donor PRPP (phosphoribosyl pyrophosphate). Cells also employ salvage pathways that recover free bases or nucleosides and convert them into nucleotides. Regulation of ribotide pools is important to ensure sufficient RNA synthesis while maintaining metabolic balance and signaling capacity.

In summary, ribotides are ribose-containing nucleotides central to RNA synthesis, energy metabolism, and cellular signaling. The term is closely aligned with ribonucleotides, with deoxyribonucleotides representing the DNA precursors.