Figure 7. MsrA repairs the oxidase activity and decreases the peroxidase activity of cytochrome c. A: Representative graph of cytochrome c oxidase activity using oxidized and repaired cyt c. Cytochrome c oxidase activity using reduced wild type cyt c gives maximum activity in this assay. When oxidized cyt c (incubated for 15 min with a 4:1 molar ratio of HOCl) is used as a substrate for cytochrome c oxidase, the activity drops by 92% to 8.3% Treatment of the oxidized cyt c (291 µM) with MsrA (1.9 µM for 2 h at 37 ºC) and 15 mM DTT leads to a seven fold increase in cyt c oxidase activity to 66% or 58% repair above the oxidized. Activity shown here is as a percentage activity of the oxidized form of cyt c. B: Representative graph of cyt c mediated peroxidase activity. The wild type protein has 9.5% of the activity of the oxidized protein. Oxidized cyt c (incubated for 15 min with 4:1 molar ratio of HOCl) gives maximal peroxidase activity. Treatment of the oxidized cyt c (291 µM) with MsrA (1.9 µM for 2 h at 37 ºC) and 15 mM DTT leads to a 40% decrease in cyt c peroxidase activity. Activity is shown here as a percentage of the activity of the oxidized form of cyt c.