Escherichia coli will reduce selenite (SeO3(2-)) and selenate (SeO4(2-)) to elemental selenium Se0. Selenium will also become incorporated into proteins as part of the amino acids selenocysteine or selenomethionine. The reaction of selenite with glutathione produces selenodiglutathione (GS-Se-GS). Selenodiglutathione and its subsequent reduction to glutathioselenol (GS-SeH) are likely the key intermediates in the possible metabolic fates of selenium. This review presents the possible pathways involving selenium in E. coli. Identification of intermediates and potential processes from uptake of the toxic oxyanions through to their detoxification will assist us in understanding the complexities of metalloid oxyanion metabolism in these bacteria.
