A spin trap study on anaerobic dehalogenation of halothane by a reconstituted liver microsomal cytochrome P-450 enzyme system

• Published in: Journal of biochemistry (Tokyo) Vol. 91; no. 1; pp. 415 - 418
• Main Authors: Fujii, K, Miki, N, Kanashiro, M, Miura, R, Sugiyama, T, Morio, M, Yamano, T, Miyake, Y
• Format: Journal Article
• Language: English
• Published: England 01.01.1982
• Subjects: Anaerobiosis; Animals; Cyclic N-Oxides; Cytochrome P-450 Enzyme System - metabolism; Electron Spin Resonance Spectroscopy; Free Radicals; Halothane - metabolism; Indicators and Reagents; Microsomes, Liver - enzymology; Nitrogen Oxides; Rabbits
• ISSN: 0021-924X
• DOI: 10.1093/oxfordjournals.jbchem.a133704

In the presence of a spin trapping reagent, N-tert-butyl-alpha-phenylnitrone, anaerobic incubation of halothane (2-bromo-2-chloro-1,1,1-trifluoroethane) with a reconstituted cytochrome P-450 enzyme system of rabbit liver microsomes exhibited an electron spin resonance spectrum containing signals of a nitroxide radical, and all components of the reconstituted system were necessary to produce the nitroxide radical. Formation of 2-chloro-1,1,1-trifluoroethane, the product of anaerobic dehalogenation of halothane by the reconstituted system, was inhibited by N-tert-butyl-alpha-phenylnitrone. These results indicate that a radical intermediate of halothane is produced during the anaerobic dehalogenation reaction, and that the radical is trapped by N-tert-butyl-alpha-phenylnitrone to form a N-tert-butyl-alpha-phenylnitrone radical adduct.