AUTOCATALYTIC PEROXIDATION OF FERROCYTOCHROME C

1. Ferricytochrome c acts as a catalyst in the peroxidation of ferrocytochrome c thereby giving rise to an autocatalytic reaction. 2. The rate of the peroxidation reaction is proportional to the concentration of H2O2 and ferricytochrome c but is independent of the concentration of ferrocytochrome c in the concentration ranges studied. 3. Integration of the rate equation, d[c3+] dt = k[c3+][H2O2], gives a theoretical expression which fits the experimental time courses for the ferrocytochrome c peroxidation reaction. 4. No direct spectral evidence was found for the formation of a catalytically active ferricytochrome c-H2O2 derivative. Kinetic evidence is presented, however, which indicates the existence of such an intermediate. 5. Ferricytochrome c was more susceptible than ferrocytochrome c to an apparent degradation reaction caused by excess H2O2, thus supporting the idea that the cytochrome c heme iron is more accessible in the oxidized form. © 1969.