TABLE 1.
Kinetic constant for different Ohr substrates
Parameters for H2O2 were obtained through a non-linear regression fit using saturating concentrations of lipoamide. Parameters for all other substrates were obtained with the secondary plots of 1/Vmax(app) and 1/Km(app) versus 1/[LA]. In the case of lipoylated enzymes SucB and PDHB, LA represents the lipoic acid covalently attached to the enzyme (1 mol of LA per 1 mol of SucB and 2 mol of LA per 1 mol of PDHB).
| Substrate | Km | kcat | kcat/Km |
|---|---|---|---|
| μm | s−1 | m−1s−1 | |
| t-BHPa | 14.51 ± 0.15 | 17.95 ± 7.25 | (2.06 ± 0.08) × 106 |
| H2O2a | 41,720.00 ± 6530.00 | 9.53 ± 0.56 | (2.30 ± 0.20) × 102 |
| Lipoamide | 44.46 ± 0.98 | 90.9 ± 4.70 | (2.06 ± 0.08) × 106 |
| PDHB | 10.93 ± 0.15 | 9.5 ± 0.20 | (0.87 ± 0.01) × 106 |
| SucB | 38.51 ± 14.12 | 17.95 ± 7.25 | (0.46 ± 0.02) × 106 |
a Parameters for t-BHP and H2O2 were calculated using free lipoamide. The results are the average of three independent experiments and represent mean ± S.D.