This proposal is directed towards the elucidation of chemical mechanisms of NADPH/02-supported cytochrome P-450-catalyzed oxidations. The key feature of the approach is that the oxygenation of a small number of carefully chosen mo compounds will be subjected to thorough scrutiny by means of combinations of physical organic probes of reaction mechanism. Reactions to be studied include benzylic hydroxylation of toluenes and ethylbenzenes, O-dealkylation of p-Nitrophenetole, and epoxidation of styrenes, 1, 7-octadiene, and related acetylenes. The probes to be utilized include kinetic deuterium isotope effects, substituent effects, stereospecificity, stereoselectivity, and deuterium shifts; they will be employed in both inter - and intramolecular experimental designs to probe both the product-forming step as well as its relationship to overall turnover. Through the unique approach of simultaneous use of combinations of these probes we will attain much greater definition than heretofore possible of changes in bonding, geometry, hybridization, and electrol distribution experienced by this sustrate as it undergoes oxygenation. In several instances these criteria will also be used to compare P-450-catalyzed oxygenations supported by aryl-iodoso compounds to these supported by NADPH/02. The information learned in this study will greatly improve our understanding of the mechanisms of substrate oxygenation, of the nature of the enzymic oxidant itself, and by inference the mechanism of the oxygen activation process.

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National Institute of General Medical Sciences (NIGMS)
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Physical Biochemistry Study Section (PB)
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University of Kansas Lawrence
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Lu, P; Alterman, M A; Chaurasia, C S et al. (1997) Heme-coordinating analogs of lauric acid as inhibitors of fatty acid omega-hydroxylation. Arch Biochem Biophys 337:1-7
Bambal, R B; Hanzlik, R P (1996) Effects of steric bulk and conformational rigidity on fatty acid omega hydroxylation by a cytochrome P450 4A1 fusion protein. Arch Biochem Biophys 334:59-66
Bambal, R B; Hanzlik, R P (1996) Active site structure and substrate specificity of cytochrome P450 4A1: steric control of ligand approach perpendicular to heme plane. Biochem Biophys Res Commun 219:445-9
Alterman, M A; Chaurasia, C S; Lu, P et al. (1995) Fatty acid discrimination and omega-hydroxylation by cytochrome P450 4A1 and a cytochrome P4504A1/NADPH-P450 reductase fusion protein. Arch Biochem Biophys 320:289-96
Chaurasia, C S; Alterman, M A; Lu, P et al. (1995) Biochemical characterization of lauric acid omega-hydroxylation by a CYP4A1/NADPH-cytochrome P450 reductase fusion protein. Arch Biochem Biophys 317:161-9
Rizk, P N; Hanzlik, R P (1995) Oxidative and non-oxidative metabolism of 4-iodoanisole by rat liver microsomes. Xenobiotica 25:143-50
Alterman, M A; Chaurasia, C S; Lu, P et al. (1995) Heteroatom substitution shifts regioselectivity of lauric acid metabolism from omega-hydroxylation to (omega-1)-oxidation. Biochem Biophys Res Commun 214:1089-94
Riley, P; Hanzlik, R P (1994) Electron transfer in P450 mechanisms. Microsomal metabolism of cyclopropylbenzene and p-cyclopropylanisole. Xenobiotica 24:1-16
Hall, L R; Hanzlik, R P (1991) N-dealkylation of tertiary amides by cytochrome P-450. Xenobiotica 21:1127-38
Hall, L R; Hanzlik, R P (1990) Kinetic deuterium isotope effects on the N-demethylation of tertiary amides by cytochrome P-450. J Biol Chem 265:12349-55

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