TABLE 1.
Kinetic parameters of the recombinant P. grassii Fe hydrogenases for H2 evolution and uptake activitya
| Enzyme | Reaction | Vmax (μmol of H2 min−1 mg−1) | Km (μM) | kcat (s−1) | kcat/Km (M−1 s−1) |
|---|---|---|---|---|---|
| 09A82 | Evolution | 2,033 | 229 | 1.8 × 105 | 7.9 × 108 |
| Uptake | 305 | 12.0 | 2.7 × 104 | 2.3 × 109 | |
| 06B09 | Evolution | 117 | 10.5 | 1.3 × 104 | 1.2 × 109 |
a
Because H2 uptake activity of the 06B09 enzyme was not detected, the parameters could not be evaluated. The parameters were determined at 30°C with MV for H2 evolution and with MB for H2 uptake and at pH 8 for the 09A82 enzyme and pH 6 for the 06B09 enzyme.