RT Book, Section A1 El-Hattab, Ayman W. A1 Scaglia, Fernando A2 Kline, Mark W. SR Print(0) ID 1182930379 T1 Disorders of Purine and Pyrimidine Metabolism T2 Rudolph's Pediatrics, 23e YR 2018 FD 2018 PB McGraw-Hill Education PP New York, NY SN 9781259588594 LK accesspediatrics.mhmedical.com/content.aspx?aid=1182930379 RD 2024/10/08 AB Purines (adenine and guanine) and pyrimidines (thymine, cytosine, and uracil) are nitrogenous bases that are essential components of nucleotides. The addition of pentose monosaccharide (ribose or deoxyribose) to a base results in a nucleoside, which can be a ribonucleoside (adenosine, guanosine, cytidine, and uridine) or a deoxyribonucleoside (deoxyadenosine, deoxyguanosine, deoxycytidine, and thymidine). Nucleotides result from the binding of nucleosides to phosphate. The binding of a nucleoside to 1, 2, or 3 phosphate groups produces nucleoside mono-, di-, or triphosphate, respectively. Nucleotides are essential for all cells. In addition to their vital role as building blocks for DNA and RNA, they serve as carriers of activated intermediates in the synthesis of a variety of complex molecules, structural components of several essential coenzymes, messengers in signal transduction pathways, regulatory components for many of the metabolic pathways, and currency for energy transfer in cells.