Table 2

The contribution of catalase and GPx to H2O2 degradation by MCF-7 cells

MCF-7 cells were plated and cultured for 5 days, and the degradation of H2O2 was monitored as described in “Materials and Methods.” Aminotriazole (50 mm) and mercaptosuccinate (0.2 mm) were present 1 h before and during exposure to H2O2. The data are presented as the first order rate constants of H2O2 degradation.

Treatmentak ± SEb (min × mg prot.) × 100
Control6.23 ± 0.30
No cells0.55 ± 0.12
AT1.96 ± 0.16
MS4.30 ± 0.20
AT+ MS0.45 ± 0.09
  • a AT, aminotriazole; MS, mercaptosuccinate.

  • b Calculation of the first order rate constants was done by regression analysis of the exponential decay curves. The analysis of H2O2 degradation in the presence of aminotriazole was based on time points starting at 15 min coincubation with both the inhibitor and H2O2 to allow for complete irreversible inhibition of catalase (31) .