Since tlic reduction of (-SS) to two (-SH) is a possible mode of activation and the reverse oxidation a possible mode of inactivation, the oxidation-reduction potentials of these components of the enzyme molecule or the potentials of the reagents which react with them are of interest. The measurement of the simpler systems involving (-SH) and (-SS-) has been undertaken as one approach to the study of the mechanism of such reactions. A further ...