Studies on the Reaction of 5, 5'-dithiobis-(2-nitorbenzoic acid) with Sulfhydryl Compounds

Abstract

Ellman reported that DTNB quantitatively reacted with sulfhydryl compounds according to the following equation to form the aromatic thiol anion whose extinction coefficient was 13, 600/M/cm at 412mμ
We reexamined the stoichiometry of this reaction by measuring the response curves of glutathione or cysteine with DTNB and isolated all the reaction products on paper chromatograms and Sepnadex G-10 gel filtration. From the investigation of chemical properties of the produtcs, we concluded that the mixed disulfide formed according to Eq. 1 sub- sequently reacted with a second sulfhydryl compound to give another aromatic thiol anion in the following manner.