Hypersensitive radical probes and the mechanisms of cytochrome P450-catalyzed hydroxylation reactions.
The title probes are precursors to kinetically calibrated, aryl-substituted cyclopropylcarbinyl radicals that rearrange with picosecond lifetimes. Applications in studies of cytochrome P450-catalyzed hydroxylation reactions are reviewed. Initially confusing results regarding lifetimes of radicals in the hydroxylation reactions were resolved when second-generation probes that distinguish between radicals and cations were employed. The results indicate that two electrophilic oxidizing species are involved in P450-catalyzed hydroxylations, an iron-oxo species that inserts oxygen and a hydroperoxo-iron species that inserts OH(+). The cationic rearrangement products are ascribed to reactions of the protonated alcohol products formed from the latter.
Department of Chemistry, Wayne State University, Detroit, Michigan 48202, USA.
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D001671:Biochemistry / Q000379:methods*; D002138:Calibration; D002412:Cations; D019362:Cytochrome P-450 CYP2B1 / Q000737:chemistry / Q000378:metabolism; D003577:Cytochrome P-450 Enzyme System / Q000737:chemistry* / Q000378:metabolism; D005609:Free Radicals; D006900:Hydroxylation; D019563:Mechanics; D010084:Oxidation-Reduction
D002412:Cations; D005609:Free Radicals; D003577:Cytochrome P-450 Enzyme System; D019362:Cytochrome P-450 CYP2B1