FIGURE 2.

Inhibition of TGR deglutathionylase activity at high GSSG concentrations. Full time courses for NADPH oxidation (A₃₄₀ decrease) at different concentrations of peptide-S-SG and/or GSSG are shown. The comparison of 40 μm peptide-S-SG (gray triangle) with 40 μm peptide-S-SG and 1 mm GSSG (gray box) time courses indicates that deglutathionylation is inhibited at high GSSG concentrations. The time courses for NADPH oxidation using 40 μm GSSG (dark gray circle), 1 mm GSSG (light gray circle), and 40 μm peptide-S-SG and 40 μm GSSG (black box) are included as references. All assays were carried out at 100 μm NADPH and 2 nm wild-type TGR. Note that in each case the overall NADPH oxidation (A₃₄₀ decrease) corresponds to the total consumption of the limiting substrate(s).