FIGURE 3.

Characterization of GSSG oxidation products M-45 and M-90. GSSG (50 μm) was incubated with HOCl (50 μm) in phosphate buffer (50 mm, pH 7.4) at 37 °C for 1 h (Control). The reaction mixture was then reduced by sodium borohydride (NaBH₄, 10 mm) at room temperature for 1 h or reacted with dinitrophenylhydrazine (DNPH, 1.5 mm) at 37 °C for 1 h at pH 2. The resulting reaction mixtures were analyzed with LC-MS and MS/MS. A, reconstructed ion chromatograms of M-45, M-90, and its reduction or derivatization products; B1–E1, mass spectrometric (MS) analysis, and B2–E2, tandem MS (MS/MS) analysis.