Table 1.
Parameters related to hydroperoxide reduction by Ohr
| Hydroperoxide | kobs, M−1⋅s−1 | Oxidative inactivation, μM | MICwt/MIC∆ohr* |
| AhpE/Ohr competition | ∼IC10† | Extent of inhibition | |
| H2O2 | (3.0 ± 0.6) × 103 | >100 | 1 |
| LAOOH | (6.3 ± 1.7) × 107 | 1 | >10 |
| OAOOH | (4.5 ± 3.5) × 108 | 1 | >10 |
| 5(S)-HpETE | (2.6 ± 1.2) × 107 | ND | ND |
| 15(S)-HpETE | (6.0 ± 3.0) × 107 | ND | ND |
| ChOOH | — | >100 | 1 |
| t-BHP | 2.0 × 106‡ | 100 | 3 |
| ONOOH | (2 ± 0.3) × 107 | ND | — |
| CHP | ND | 100 | 3 |
kobs, observed rate constant; ND, not determined.
*
Ratio of MICwt (minimal concentration of hydroperoxide that inhibits growth of wild-type strain) to MIC∆ohr (minimal concentration of hydroperoxide that inhibits growth of ∆ohr strain).
†
Defined here as the amount of hydroperoxide that provokes 10% Ohr inactivation.
‡
Because Ohr is several orders of magnitude more efficient than MtAhpE in the reduction of t-BHP, it was not possible to determine this rate constant through the competitive assay. Instead, data from the study by Cussiol et al. (23) were added here.