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Selenium Proteins Containing Selenocysteine

  1. August Böck

Published Online: 15 MAR 2006

DOI: 10.1002/0470862106.ia215

Encyclopedia of Inorganic Chemistry

Encyclopedia of Inorganic Chemistry

How to Cite

Böck, A. 2006. Selenium Proteins Containing Selenocysteine. Encyclopedia of Inorganic Chemistry. .

Author Information

  1. University of Munich, Department Biologie 1, Munich, Germany

Publication History

  1. Published Online: 15 MAR 2006


Selenium is incorporated in the form of the nonstandard amino acid selenocysteine into selected proteins of organisms belonging to all three lines of descent. The majority of these proteins, which contain selenocysteine in the active site, catalyze oxidation–reduction reactions and are involved in numerous biochemical and regulatory processes, which are indispensable for the organism. Because of the higher chemical reactivity of selenocysteine in comparison to cysteine, selenoenzymes display a greatly increased rate of catalysis. Apart from its biochemical function, selenocysteine is also unique since its incorporation is DNA-encoded and its cotranslational insertion follows a route independent in many features from the path of insertion of the 20 classical amino acids. Selenocysteine, therefore, can be considered the 21st amino acid.


  • selenoproteins;
  • selenoenzymes;
  • nonstandard amino acid;
  • tRNASec;
  • translation factor SelB;
  • selenocysteine synthesis;
  • selenophosphate