Formation of a selenium-substituted rhodanese by reaction with selenite and glutathione: possible role of a protein perselenide in a selenium delivery system

Proc Natl Acad Sci U S A. 2001 Aug 14;98(17):9494-8. doi: 10.1073/pnas.171320998. Epub 2001 Aug 7.


Selenophosphate is the active selenium-donor compound required by bacteria and mammals for the specific synthesis of Secys-tRNA, the precursor of selenocysteine in selenoenzymes. Although free selenide can be used in vitro for the synthesis of selenophosphate, the actual physiological selenium substrate has not been identified. Rhodanese (EC ) normally occurs as a persulfide of a critical cysteine residue and is believed to function as a sulfur-delivery protein. Also, it has been demonstrated that a selenium-substituted rhodanese (E-Se form) can exist in vitro. In this study, we have prepared and characterized an E-Se rhodanese. Persulfide-free bovine-liver rhodanese (E form) did not react with SeO(3)(2-) directly, but in the presence of reduced glutathione (GSH) and SeO(3)(2-) E-Se rhodanese was generated. These results indicate that the intermediates produced from the reaction of GSH with SeO(3)(2-) are required for the formation of a selenium-substituted rhodanese. E-Se rhodanese was stable in the presence of excess GSH at neutral pH at 37 degrees C. E-Se rhodanese could effectively replace the high concentrations of selenide normally used in the selenophosphate synthetase in vitro assay in which the selenium-dependent hydrolysis of ATP is measured. These results show that a selenium-bound rhodanese could be used as the selenium donor in the in vitro selenophosphate synthetase assay.

MeSH terms

  • Animals
  • Cattle
  • Dithiothreitol / pharmacology
  • Glutathione / metabolism
  • Iodoacetamide / pharmacology
  • Oxidation-Reduction
  • Phosphates / metabolism
  • Selenium / chemistry*
  • Selenium Compounds / metabolism
  • Selenocysteine / metabolism
  • Sodium Selenite / metabolism
  • Thiosulfate Sulfurtransferase / chemistry*


  • Phosphates
  • Selenium Compounds
  • Selenocysteine
  • selenophosphate
  • Thiosulfate Sulfurtransferase
  • Glutathione
  • Selenium
  • Sodium Selenite
  • Dithiothreitol
  • Iodoacetamide