FIGURE 6.

Time course of GSSG, M-45, and M-90 reduction catalyzed by glutathione reductase. 20 μm GSSG, M-45, or M-90 were added to a reaction mixture containing 22 nm glutathione reductase and 570 μm 5,5′-dithiobis(2-nitrobenzoic acid) in phosphate buffer (100 mm, pH 7.5) containing 1 mm EDTA. After a 5-min incubation, the reaction was initiated by adding 500 μm NADPH. Absorbance at 412 nm was recorded for 5-thio(2-nitrobenzoic acid) in a kinetic mode every 15 s for 2 min, using a plate reader. The results are expressed as mean ± S.D. from 3 experiments.