FIGURE 7.
GR activity of TGR mutants. Time courses obtained for the GR activity of wild-type TGR and its mutants are shown. In all cases the reaction was started by the addition of the enzymes at the indicated final concentrations. A, comparison of the GR activity of TGRGCUG, TGRGCCG, TGRGC*, and TRGCUG at 31 μm GSSG and 125 μm NADPH. B, the GR activity of TGRGUCG at different enzyme concentrations was evaluated at 31 μm GSSG and 125 μm NADPH. C, the effect of GSH addition on the hysteretic behavior of TGRGUCG was studied by including GSH at 1 mm in a reaction mixture containing 1 mm GSSG, 125 μm NADPH, and 25 nm TGRGUCG. The enzyme concentrations for selenoproteins (TGRGCUG, TRGCUG, and TGRGUCG) were corrected according to their selenium contents.