Figure 6.

Kinetic analysis of the reduction of H₂O₂ by wild type, Y193G and Y193M Prx2. (A) NADPH-linked peroxidase activity of wild-type Prx2 is shown in black, Y193G Prx2 in dark gray and Y193M Prx2 in light gray. Ten µM H₂O₂ was added to start the reactions and consumption of NADPH was followed at 340 nm. (B) NADPH-linked peroxidase activity was followed for the Y193G Prx2 mutant in the same conditions, using 10 µM H₂O₂ (black), 20 µM H₂O₂ (dark gray) or 50 µM H₂O₂ (light gray). (C) Oxidation of Y193G Prx2 followed by intrinsic fluorescence. Dependence of the kinetic constant of the slow phase on H₂O₂ concentration.