Encyclopedia of Astrobiology

Living Edition
| Editors: Muriel Gargaud, William M. Irvine, Ricardo Amils, Henderson James Cleaves, Daniele Pinti, José Cernicharo Quintanilla, Michel Viso


  • Henderson James (Jim) CleavesII
Living reference work entry
DOI: https://doi.org/10.1007/978-3-642-27833-4_1371-4


In biochemistry, a ribonucleoside is an organic molecule derived from the condensation of a nitrogenous base and the C1 atom of ribose via a glycoside linkage. Examples of pyrimidine ribonucleosides include uridine and cytidine. Thymine ribonucleoside is sometimes called 5-methyluridine, while thymidine represents deoxynucleoside of thymine. Pyrimidine ribosides are linked via their N1 nitrogen atoms. The purine ribosides include adenosine and guanosine, linked via their N9 ring atoms. The glycoside linkage may be α- or β-, depending on which face of the ribose ring the nitrogen heterocycle is bonded on. Biological ribosides are β-linked. Nucleosides are phosphorylated to give nucleotides.

See Also


Nucleic Acid Nitrogen Atom Bioorganic Chemistry Organic Molecule Nitrogenous Base 
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Copyright information

© Springer-Verlag Berlin Heidelberg 2014

Authors and Affiliations

  1. 1.Earth-Life Science Institute (ELSI)Tokyo Institute of TechnologyMeguro-kuJapan
  2. 2.Institute for Advanced StudyPrincetonUSA
  3. 3.Blue Marble Space Institute of ScienceWashingtonUSA
  4. 4.Center for Chemical EvolutionGeorgia Institute of TechnologyAtlantaUSA