EFFECT OF PHYSICAL FACTORS ON REACTIONS OF HORSE-RADISH PEROXIDASE COMPLEXES WITH REDUCED CYTOCHROME C.

This investigation concerns the effect of certain physical factors-viscosity, dielectric constant, ionic strength, and temperature of the medium-on the reaction of hydrogen peroxide and ferrocytochrome c in the presence of the enzyme horse-radish peroxidase. From study of the effects of viscosity and dielectric constant, it was concluded that the reaction between the secondary complex of hydrogen peroxide and enzyme on the one hand and ferrocytochrome c on the other is controlled by diffusion in media of high viscosity and by electrostatic effects at low viscosities. With respect to ionic strength, the data at pH 4.7 indicated a dipole-dipole interreaction. The temperature dependence of the over-all reaction had a Q(10) of 1.25.