Fenyl radicals

The first step of the reduction process involves adsorption of oxygen at the reduced Fe VCu center to form an Fe -02 superoxide adduct with subsequent formation of an intermediate comprised of oxidized Cu an Fe =0 fenyl radical, and a peripheral phenoxide radical (Fig. 7.7). The oxidized intermediate is then reduced directly to water by simultaneous transfer of four electrons [35],... 

Complex 1, an oxo-fenyl(FeIV) porphyrin it-cation radical has been well characterized for catalase, horseradish peroxidase, and ligninase, and all of the chemistry of cytochrome P-4S0 points towards a similar high oxidation state intermediate. In the enzymatic systems this intermediate is known as compound I. 

Then the fenyl ion either reacts with water to form the hydroxyl radical, or oxidizes another Fe ion... 

The most probable mechanism of the reaction is an oxygen activation with formation of the fenyl stmcture followed by the formation a free methyl radical reacting with oxygen atom. 

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