| Modification Notes |
SEPHS2 (selenophosphate synthetase 2), also known as SPS2, Selenium donor protein 2 or Selenide water dikinase 2, is a member of the selenophosphate synthetase 1 family of proteins. SEPHS2 is one of two mammalian homologs of the eubacteria selenophosphate synthetase protein SelD. SelD is an enzyme that generates the selenium donor for the biosynthesis of selenocysteine. SEPHS2 has a similar function to SelD and specifically catalyzes the formation of selenophosphate (the active selenium donor) from selenide and ATP. The knockdown of SEPHS2 expression greatly impairs selenoprotein biosynthesis, suggesting that SEPHS2 is the mammalian enzyme responsible for generating the selenium donor and regulating selenoprotein synthesis. In addition, SEPHS2 is itself a selenoprotein, implying that it may also function as an auto-regulator. |