The Influence of Electrode Potentials on the Extent of Reduction of Cystine in Hair Fibers by Reducing Agents

Abstract

The effect of reducing agents on hair fibers was measured by studying the relaxation curves of fibers kept at constant elongation in a solution of the reagent. Where reduc tion occurred, the extent of reduction, as measured by the final equilibrium stress level, was dependent on the electrode potential of the reagent. The reduction of stress cor responded to reduction of cystine disulfide linkages within the fiber as shown by chemical analyses of treated hair fibers. The dependence of the amount of reduction on the reagent potential indicates that the cystine residues within the keratin fiber exhibit dissimilar E° values.