High-performance liquid chromatography method for the determination of protein-glutathione mixed disulfide.

We have developed an efficient and sensitive method for the quantification of picomole quantities of protein-glutathione and protein-cysteine mixed disulfides in ocular lens. Performic acid oxidation releases glutathione and cysteine from the protein-mixed disulfides as glutathione sulfonic acid and cysteic acid, respectively. The sulfonic acids are derivatized with phenylisothiocyanate, and the phenylthiocarbamyl derivatives are separated by HPLC using a reversed-phase ODS column, equilibrated with 0.14 M sodium acetate, containing 0.1% triethylamine and 6% acetonitrile.