Thiol-disulfide Transhydrogenase from Baker's Yeast and a New Method for the Direct Assay of an Enzyme-catalyzed Thiol-disulfide Interchange Activity

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This paper presents a study on the enzyme reduction of the disulfide bond and the following results have been found.
In enzyme preparation, antioxidants showed a stability effect and EDTA appeared to have both enzyme stabilization and solubilization. On the distribution of the enzyme activity in subcellular fractions, the water soluble fraction appeared to contain the major released enzyme activity. The enzyme was inhibited with several metals. Hg²⁺ and transition metals were the most toxic. The substrate specificity of this enzyme was wide for the low molecular substrates, but the protein disulfide reducing activity was not detected in this preparation. It was assumed that the thiol-disulfide transhydrogenase was coupled with glutathione reductase and the disulfide substrates were reduced by the system involving the two enzymes. A new method for the direct recording of an enzyme-catalyzed thiol-disulfide interchange using diphenyl disulfide and p, p'-dinitro diphenyl disulfide was devised.