Activation of iodine into a free-radical intermediate by superoxide: a physiologically significant step in the iodination of tyrosine.
A pivotal biochemical event in the thyroid physiology is identified unravelling a superoxide anion radical-mediated activation of iodine into an active I.- form, which could be the intermediate that is incorporated onto tyrosine. This active iodine species gives fairly stable spin-adducts with PBN that could be characterized using EPR spectroscopy. Thus, a long-lasting puzzle regarding the iodine intermediate formed before iodination of tyrosine seems to be solved.
Verma
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School of Life Sciences, Devi Ahilya Vishwavidyalaya, Indore, India.
Kumar
G P
GP
Laloraya
M
M
Singh
A
A
D000818:Animals; D003497:Cyclic N-Oxides; D004578:Electron Spin Resonance Spectroscopy; D005609:Free Radicals; D007455:Iodine / Q000378:metabolism*; D008297:Male; D008954:Models, Biological; D009589:Nitrogen Oxides; D010084:Oxidation-Reduction; D011817:Rabbits; D013113:Spin Labels; D013481:Superoxides / Q000378:metabolism*; D014443:Tyrosine / Q000378:metabolism*
D003497:Cyclic N-Oxides; D005609:Free Radicals; D009589:Nitrogen Oxides; D013113:Spin Labels; D013481:Superoxides; C029217:phenyl-N-tert-butylnitrone; D014443:Tyrosine; D007455:Iodine