FIG. 3.

Thioredoxin-dependent peroxidase activities of 2-Cys Prx, PrxII, 1-Cys Prx, PrxQ1, and PrxQ2. Reaction mixtures contained 50 mM HEPES-NaOH (pH 7.0), 0.2 mM DTT, 4 μM Trx, 100 μM H₂O₂, and 25 μg Prx in a final volume of 250 μl. This concentration corresponds to 5 μM for 2-Cys Prx, 1-Cys Prx, and PrxII and to 5.5 μM for PrxQ1 and PrxQ2. The concentration of H₂O₂ was measured at 0, 10, 20, and 30 min after hydrogen peroxide addition. As a control, for each peroxiredoxin an assay was performed in the absence of thioredoxins but in the presence of DTT (dashed lines). The values at each time point are averages from at least three independent experiments.