1-chloro-2,2,2-trifluoroethyl radical: Formation from halothane by human cytochrome P-450 in reconstituted vesicles and binding to phospholipids

We report the first complete structural characterization of a metabolically-produced halocarbon radical bound to a phospholipid. Human cytochrome P-450 and NADPH cytochrome P-450 reductase were reconstituted into vesicles composed of dioleoylphosphatidylcholine and egg phosphatidylethanolamine. The vesicles were incubated under argon with NADPH and ¹⁴C]-halothane (1-¹⁴C]-2-bromo-2-chloro-1,1,1-trifluoroethane), the dioleoylphosphatidylcholine fraction was isolated and subjected to transesterification. Separation of the resulting fatty acid methyl esters resulted in one radioactive fraction which gas chromatography-mass spectrometry revealed to be a mixture of 9- and 10-(1-chloro-2,2,2-trifluoroethyl)-stearate methyl ester.