One-electron reduction in oxyform of hemoproteins

The reaction of the hydrated electron with oxyform of hemoproteins such as MbO2 and oxyperoxidase was investigated by the use of pulse radiolysis method. MbO2 was reduced by hydrated electrons to form the hydrogen peroxide-induced compound, the so-called "ferryl" Mb. On the other hand, the oxyform of diacetydeuteroperoxidase was also reduced by hydrated electrons to form Compound I of this enzyme. Both reactions are found to follow second order kinetics with rate constants of 4 X 10(10) M-1 s-1 at pH 7.4, without detection of intermediates, i.e. 1-electron reduction.