Influence of several perturbants on the rate of autoxidation of horse heart ferrocytochrome c.

The effect of several different types of perturbants and pH on the rate of autoxidation of horse heart ferrocytochrome c was investigated. The kinetic behavior is unique to each perturbant used. Rates of autoxidation followed first-order kinetics over the time span (0-180 min) studied. The Cl- and Br- anions exhibit an initial increase in the rate of autoxidation up to 100 mM, followed by a decrease in kinetics at 500 mM anion concentration. The ClO4- anion exhibits only an increase in the rate of autoxidation with increasing ionic strength, where as, propylurea, a hydrophobic perturbant, is not effective in altering the rate of autoxidation at equivalent concentrations. These studies suggest that the perturbations of the reduced form of cytochrome c in solution involve mainly non-specific solvent effects.