Abstract
The mechanism of alkane hydroxylation by rat hepatic cytochrome P450 enzymes has been studied with hypersensitive radical probes, precursors to radicals that have lifetimes of only a few picoseconds. The results indicate that some of the previous evidence for a radical intermediate in the hydroxylation reaction arose from production of an unanticipated cationic species and that the hydroxylation occurs by a non-synchronous insertion process with a “radical” lifetime of only ca. 70 femtoseconds.
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References
Mueller, E.J., Loida, P.J. and Sligar, S.G. (1995) Twenty-five Years of P450cam Research: Mechanistic Insights into Oxygenase Catalysis, in P.R. Ortiz de Montellano (ed.) Cytochrome P450 Structure, Mechanism and Biochemistry, Plenum: New York. 2nd Ed., p. 83–124.
Groves, J.T. and Han, Y.-Z. (1995) Models and Mechanisms of Cytochrome P450 Action, in P.R. Ortiz de Montellano (ed.) Cytochrome P450 Structure, Mechanism and Biochemistry, Plenum: New York. 2nd Ed., p. 3–48.
Hamilton, G.A. (1974) Chemical Models and Mechanisms for Oxygenases, in O. Hayaishi (ed.) Molecular Mechanisms of Oxygen Activation, Academic: New York. p. 405–451.
Groves, J.T., McClusky, G.A., White, R.E. and Coon, M.J. (1978) Aliphatic Hydroxylation by Highly Purified Liver Microsomal Cytochrome P-450. Evidence for a Carbon Radical Intermediate, Biochem. Biophys. Res. Commun. 81, 154–160.
Suckling, C.J. (1988) The Cyclopropyl Group in Studies of Enzyme Mechanism and Inhibition, Angew. Chem. Int. Ed. Eng. 27, 537–552.
White, R.E., Groves, J.T. and McClusky, G.A. (1979) Electronic and Steric Factors in Regioselective Hydroxylation Catalyzed by Purified Cytochrome P450, Acta Biol. Med. Ger. 38, 475–489.
Groves, J.T. and Subramanian, D.V. (1984) Hydroxylation by Cytochrome P-450 and Metalloporphyrin Models. Evidence for Allylic Rearrangement, J. Am. Chem. Soc. 106, 2177–2181.
Ortiz de Montellano, P.R. and Stearns, R.A. (1987) Timing of the Radical Recombination Step in Cytochrome P-450 Catalysis with Ring-Strained Probes, J. Am. Chem. Soc. 109, 3415–3420.
Jamieson, C., Walton, J.C. and Ingold, K.U. (1980) Radical Reactions of Bicyclo[2.1.0]pentane, J. Chem. Soc., Perkin Trans. 2, 1366–1371.
Griller, D. and Ingold, K.U. (1980) Free-Radical Clocks, Acc. Chem. Res. 13, 317–323.
Newcomb, M. (1993) Competition Methods and Scales for Alkyl Radical Reaction Kinetics, Tetrahedron 49, 1151–1176.
Bowry, V.W., Lusztyk, J. and Ingold, K.U. (1991) Calibration of a New Horology of Fast Radical Clocks. Ring-Opening Rates for Ring-alkyl-substituted and alpha-alkyl-substituted Cyclopropylcarbinyl Radicals and for the Bicyclo[2.1.0]pent-2-yl Radical, J. Am. Chem. Soc. 113, 5687–5698.
Newcomb, M., Manek, M.B. and Glenn, A.G. (1991) Ring Opening and Hydrogen Atom Transfer Trapping of the Bicyclo[2.1.0]pent-2-y1 Radical., J. Am. Chem. Soc. 113, 949–958.
Newcomb, M., Johnson, C.C., Manek, M.B. and Varick, T.R. (1992) Picosecond Radical Kinetics. Ring Openings of Phenyl Substituted Cyclopropylcarbinyl Radicals, J. Am. Chem. Soc. 114, 10915–10921.
Martin-Esker, A.A., Johnson, C.C., Homer, J.H. and Newcomb, M. (1994) Picosecond Radical Kinetics. Fast Ring Openings of Constrained, Aryl-Substituted Cyclopropylcarbinyl Radicals, J. Am. Chem. Soc. 116, 9174–9181.
Bowry, V.W. and Ingold, K.U. (1991) A Radical Clock Investigation of Microsomal Cytochrome P-450 Hydroxylation of Hydrocarbons. Rate of Oxygen Rebound, J. Am. Chem. Soc. 113, 5699–5707.
Atkinson, J.K. and Ingold, K.U. (1993) Cytochrome P450 Hydroxylation of Hydrocarbons: Variation in the Rate of Oxygen Rebound Using Cyclopropyl Radical Clocks Including Two New Ultrafast Probes, Biochemistry 32, 9209–9214.
Atkinson, J.K., Hollenberg, P.F., Ingold, K.U., Johnson, C.C., Le Tadic, M.-H., Newcomb, M. and Putt, D.A. (1994) Cytochrome P450-Catalyzed Hydroxylation of Hydrocarbons: Kinetic Deuterium Isotope Effects for the Hydroxylation of an Ultrafast Radical Clock, Biochemistry 33, 10630–10637.
Newcomb, M., Le Tadic, M.H., Putt, D.A. and Hollenberg, P.F. (1995) An Incredibly Fast Apparent Oxygen Rebound Rate Constant for Hydrocarbon Hydroxylation by Cytochrome P-450 Enzymes, J. Am. Chem. Soc. 117, 3312–3313.
Ruzicka, F., Huang, D.-S., Donnelly, M.I. and Frey, P.A. (1990) Methane Monooxygenase Catalyzed Oxygenation of 1,1-Dimethylcyclopropane. Evidence for Radical and Carbocationic Intermediates, Biochemistry 29, 1696–1700.
Newcomb, M. and Chestney, D.L. (1994) A Hypersensitive Mechanistic Probe for Distinguishing Between Radical and Carbocation Intermediates, J. Am. Chem. Soc. 116, 9753–9754.
Newcomb, M., Le Tadic-Biadatti, M.H., Chestney, D.L., Roberts, E.S. and Hollenberg, P.F. (1995) A Nonsynchronous Concerted Mechanism for Cytochrome P-450 Catalyzed Hydroxylation, J. Am. Chem. Soc. 117, 12085–12091.
Le Tadic-Biadatti, M.H. and Newcomb, M. (1996) Picosecond Radical Kinetics. Rate Constants for Ring Opening of (2-Alkoxy-3-phenylcyclopropyl)methyl Radicals, J. Chem. Soc., Perkin Trans. 2, 0000–0000.
Le Tadic-Biadatti, M.H., unpublished results.
Tachikawa, H., Hokari, N. and Yoshida, H. (1993) An Abinitio MO Study on Hydrogen Abstraction from Methanol by Methyl Radical, J. Phys. Chem. 97, 10035–10041.
Choi, S.-Y., Eaton, P.E., Hollenberg, P.F., Liu, K.E., Lippard, S.J., Newcomb, M., Putt, D.A. and Upadhyaya, S.P. (1996) Regiochemical Variations in Reactions of Methylcubane with tert-Butoxyl Radical, Cytochrome P-450 Enzymes, and a Methane Monooxygenase System, J. Am. Chem. Soc. 118, 0000–0000.
Zaks, A. and Dodds, D.R. (1995) Chloroperoxidase-Catalyzed Asymmetric Oxidations: Substrate Specificity and Mechanistic Study, J. Am. Chem. Soc. 117, 10419–10424.
Fu, H., Newcomb, M. and Wong, C.-H. (1991) Pseudomonas-Oleovorans Monooxygenase Catalyzed Asymmetric Epoxidation of Ally’ Alcohol Derivatives and Hydroxylation of a Hypersensitive Radical Probe with the Radical Ring Opening Rate Exceeding the Oxygen Rebound Rate, J. Am. Chem. Soc. 113, 5878–5880.
Liu, K.E., Johnson, C.C., Newcomb, M. and Lippard, S.J. (1993) Radical Clock Substrate Probes and Kinetic Isotope Effect Studies of the Hydroxylation of Hydrocarbons by Methane Monooxygenase, J. Am. Chem. Soc. 115, 939–947.
Wilkinson, B., Liu, K.E., Valentine, A.M., Komar-Panacucci, S., Morimoto, H., Williams, P.G., Lippard, S.J., and Floss, H.G., unpublished results cited in footnote 24 of ref [26].
Newcomb, M., Simakov, P.A. and Park, S.U. (1996) Hypersensitive Radical Probe Studies of Gif Oxidations, Tetrahedron Lett. 37, 819–822.
Priestley, N.D., Floss, H.G., Froland, W.A., Lipscomb, J.D., Williams, P.G. and Morimoto, H. (1992) Cryptic Stereospecificity of Methane Monooxygenase, J. Am. Chem. Soc. 114, 7561–7562.
Sears, T.J., Johnson, P.M., Jin, P. and Oatis, S. (1996) Infrared Laser Transient Absorption Spectroscopy of the Ethyl Radical, J. Chem. Phys. 104, 781–792.
Barton, D.H.R. and Doller, D. (1992) The Selective Functionalization of Saturated Hydrocarbons. Gif Chemistry, Acc. Chem. Res. 25, 504–512.
Hollis, R., Hughes, L., Bowry, V.W. and Ingold, K.U. (1992) Calibration of a Fast Benzylic Radical Clock Reaction, J. Org. Chem. 57, 4284–4287.
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Newcomb, M., Le Tadic-Biadatti, MH. (1997). Hypersensitive Probing for Radicals in Cytochrome P450 Hydroxylations. In: Minisci, F. (eds) Free Radicals in Biology and Environment. NATO ASI Series, vol 27. Springer, Dordrecht. https://doi.org/10.1007/978-94-017-1607-9_7
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DOI: https://doi.org/10.1007/978-94-017-1607-9_7
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