Formation of complexes between microsomal cytochrome P-450-Fe(II) and nitrosoarenes obtained by oxidation of arylhydroxylamines or reduction of nitroarenes in situ.
A cytochrome P-450 complex exhibiting a Soret peak at 454 nm is formed by direct interaction of nitrosobenzene with NADPH-reduced rat liver microsomes in anaerobic conditions, by reaction of phenylhydroxylamine with aerobic microsomes or during nitrobenzene reduction by NADPH-reduced or dithionite-reduced microsomes. In the latter conditions, the complex formation is only transient as it is unstable to dithionite. Analogous reactions with myoglobin lead to the previously described myoglobin-Fe(II)-nitrosobenzene complex which has similar properties to those of the 454-nm-absorbing cytochrome P-450 complex. This analogy, together with the various conditions of its formation, strongly indicates that it is a cytochrome-P-450-Fe(II)-nitrosobenzene complex. The corresponding complex with the 4-chloro-nitrosobenzene ligand is formed in similar conditions. Cytochrome P-450-Fe(II) complexes with nitrosoarenes seem less stable than the previously described complexes with nitrosoalkanes.
D000818:Animals; D003577:Cytochrome P-450 Enzyme System / Q000378:metabolism*; D004227:Dithionite / Q000494:pharmacology; D005290:Ferric Compounds / Q000378:metabolism; D005296:Ferrous Compounds / Q000378:metabolism*; D006898:Hydroxylamines / Q000378:metabolism*; D007501:Iron / Q000378:metabolism*; D008297:Male; D008706:Methemoglobin / Q000378:metabolism; D008862:Microsomes, Liver / Q000378:metabolism*; D009211:Myoglobin / Q000378:metabolism; D009249:NADP / Q000378:metabolism; D009578:Nitrobenzenes / Q000378:metabolism*; D009603:Nitroso Compounds / Q000378:metabolism*; D051381:Rats
D005290:Ferric Compounds; D005296:Ferrous Compounds; D006898:Hydroxylamines; D009211:Myoglobin; D009578:Nitrobenzenes; D009603:Nitroso Compounds; D004227:Dithionite; C012484:phenylhydroxylamine; D009249:NADP; D008706:Methemoglobin; D003577:Cytochrome P-450 Enzyme System; D007501:Iron; C012456:nitrosobenzene