A mammalian reductive deiodinase has broad power to dehalogenate chlorinated and brominated substrates.
Iodotyrosine deiodinase is essential for iodide homeostasis and proper thyroid function in mammals. This enzyme promotes a net reductive deiodination of 3-iodotyrosine to form iodide and tyrosine. Such a reductive dehalogenation is uncommon in aerobic organisms, and its requirement for flavin mononucleotide is even more uncommon in catalysis. Reducing equivalents are now shown to transfer directly from the flavin to the halogenated substrate without involvement of other components typically included in the standard enzymatic assay. Additionally, the deiodinase has been discovered to act as a debrominase and a dechlorinase. These new activities expand the possible roles of flavin in biological catalysis and provide a foundation for determining the mechanism of this unusual process.
Department of Chemistry and Biochemistry, University of Maryland, College Park, Maryland 20742, USA.
Patrick M
PM
McTamney
Steven E
SE
Rokita
D004578:Electron Spin Resonance Spectroscopy; D005415:Flavins / Q000737:chemistry / Q000378:metabolism; D006842:Hydrocarbons, Brominated / Q000737:chemistry* / Q000378:metabolism; D006843:Hydrocarbons, Chlorinated / Q000737:chemistry* / Q000378:metabolism; D007453:Iodide Peroxidase / Q000737:chemistry* / Q000378:metabolism; D007700:Kinetics; D010084:Oxidation-Reduction
D005415:Flavins; D006842:Hydrocarbons, Brominated; D006843:Hydrocarbons, Chlorinated; D007453:Iodide Peroxidase