Characterization of two alkyl hydroperoxide reductase C homologs alkyl hydroperoxide reductase C_H1 and alkyl hydroperoxide reductase C_H2 in Bacillus subtilis

Figure 7 Susceptibility of AhpC_H1 with AhpC_H2 to inactivation by hydrogen peroxide. Peroxidase activity of AhpC_H1 (A) and AhpC_H2 (B) was continuously monitored by the decrease in 340-nm absorbance due to NADPH oxidation at 25 °C in the presence of 50 mmol/L of Hepes-NaOH buffer, pH 7.4, containing 1 mmol/L EDTA, 100 nmol/L of E. coli Trx reductase, 0.14 mmol/L of NADPH, 5 μmol/L of E. coli Trx, 2 μmol/L of AhpC_H1 and AhpC_H2 and varying concentrations of H2O2. Control, absorbance without H2O2; C: Changes in initial peroxidase activity rate depending on H2O2 concentration. AhpC_H1 was resistant, while AhpC_H2 was sensitive to inactivation by H₂O₂.