Mitochondrial ROS scavenging ability following uncoupling or permeability transition. (A) Representative traces of ROS scavenging ability measurements. In trace 1, SOD, HRP and Amplex Red were added from start and 2 μM H2O2 was added at 7 min to obtain a reference value. In trace 2–5, HRP and Amplex Red were added 0.5, 1, 1.5 and 2 min after H2O2 administration, respectively, to measure the residual H2O2 concentrations and hence determine the mitochondrial ROS scavenging ability. (B) Same as panel A but with 1 mM Ca2+ present to induce permeability transition. (C) Mean residual H2O2 concentrations in the mitochondrial suspensions following addition of 2 μM H2O2. Experiments were performed with control, 225 pM valinomycin (Val), 200 nM CCCP and calcium-treated mitochondria. (D) Comparison of mitochondrial ROS production and ROS scavenging rates in heart mitochondria. Note the logarithmic scale. ROS scavenging rate following H2O2 addition was calculated over the first minute following addition of H2O2 and ROS production rate was calculated in the same set of experiments before addition of exogenous H2O2 for those samples where the Amplex Red system was present from start. Values are means ± S.E.M.* indicates p < 0.05 compared to control.
Morota et al. BMC Cell Biology 2013 14:40 doi:10.1186/1471-2121-14-40