Aliphatic hydroxylation by highly purified liver microsomal cytochrome P-450. Evidence for a carbon radical intermediate

doi:10.1016/0006-291X(78)91643-1

Biochemical and Biophysical Research Communications

Volume 81, Issue 1, 15 March 1978, Pages 154-160

https://doi.org/10.1016/0006-291X(78)91643-1 Get rights and content

Abstract

The oxidation of norbornane by a reconstituted liver cytochrome P-450 system affords $exo$ - and $endo$ -2-norborneol in a ratio of 3.4:1. The ratio of these products was found to be 0.76:1 when $exo,exo,exo,exo$ -2,3,5,6-tetradueteronorbornane was oxidized. Analysis of the mass spectra of the products from the deuterated hydrocarbon showed that 25% of the $exo$ -norborneol contained four deuterium atoms whereas 9% of the $endo$ -norborneol contained three deuterium atoms. These results, which indicate a very large isotope effect ( $k_{H} k_{D} = 11.5±1$ ) and a significant amount of epimerization for the hydroxylation of norbornane by cytochrome P-450, suggest an initial hydrogen abstraction to give a carbon radical intermediate.

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Citation Excerpt :
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Aliphatic hydroxylation by highly purified liver microsomal cytochrome P-450. Evidence for a carbon radical intermediate

Abstract

Arch. Biochem. Biophys

Biochem. Biophys. Res. Commun

J. Biol. Chem

J. Biol. Chem

Biochem. Biophys. Res. Commun

Drug. Metab. and Disp

J. Amer. Chem. Soc

Croat. Chem. Acta

J. Amer. Chem. Soc

J. Amer. Chem. Soc