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High affinity selenium uptake in a keratinocyte model
Author(s) -
Ganyc Dennis,
Self William T.
Publication year - 2008
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/j.febslet.2007.12.022
Subject(s) - selenium , selenide , chemistry , oxyanion , selenate , biochemistry , kinetics , selenoprotein , enzyme , glutathione , organic chemistry , catalysis , physics , glutathione peroxidase , quantum mechanics
The distribution of selenium in mammals has been recently shown to be mediated primarily by selenoprotein P. Even in the absence of selenoprotein P, selenium is distributed from the liver into all organs and tissues when supplemented in the diet. The form of selenium that is actively taken up by mammalian cells at trace concentrations has yet to be determined. We used a human keratinocyte model to determine whether reduction of the oxyanion selenite ( SeO 3 2 ‐ ) to the more reduced form of selenide (HSe − ) would affect uptake. Indeed a reduced form of selenium, presumably selenide, was actively transported into keratinocytes and displayed saturation kinetics with an apparent K m of 279 nM. ATPase inhibitors blocked the uptake of selenide, as did the competing anions molybdate and chromate, but not sulfate. These results suggest that the small molecule form of selenium that is distributed in tissues is hydrogen selenide, despite its sensitivity to oxygen and reactivity to thiols.