The oxidation-reduction potentials of cytochrome C

Abstract

Cytochrome C forms a reversible oxidation-reduction system, involving only one equivalent. The variation of the potential with change in pH has been studied between pH 4.59 and 9.20. In the physiological range of pH, the characteristic potential is between that of methylene blue and that of the indophenols. Eo at pH 7.0 is +0.123 V. The relation between oxidation-reduction potential and velocity of reaction has been analyzed and the conclusion was reached that enzyme specificity and not potential determines rates of reactions in biological systems.