Figure 2.

Initial characterization of the PKG Iα oxidative phenotype. A, cGMP-dependent activation under reducing (solid line; n = 12) and oxidizing (500 μm H₂O₂, 30 min; dashed line; n = 16) conditions. B, PKG Iα activity plotted against increasing concentrations of H₂O₂. Activity was measured in the absence (black; n = 4) and presence of cGMP (red; 4 μm, n = 4). The concentration of H₂O₂ (500 μm) that resulted in the greatest increase in basal activity is highlighted in the boxed region. C, time course examining PKG Iα oxidation with 500 μm cGMP wherein the -fold activity (V_max/V_min) was monitored (n = 4). D, representative nonreducing, denaturing SDS-PAGE of PKG Iα exposed to increasing concentrations of H₂O₂. The dashed line indicates the point at which the concentration of hydrogen peroxide overcomes the concentration of TCEP in the buffer. H₂O₂ values corrected for the presence of TCEP are shown in red. Where shown, data are represented as the mean ± S.D. (error bars).