TABLE 2.
Dependency of oxygen-evolving activity on the artificial electron acceptor quinones
The rates of oxygen evolution were measured at 30 °C with various concentrations of 2,5-DCBQ and duroquinone at 2 μg of Chl/ml. The plots were fitted using data points with quinone concentrations below the occurrence of inhibition to the rectangular hyperbola using a Levenberg-Marquardt regression algorithm by KaleidaGraph version 4.0 for Macintosh (Synergy Software, Reading, PA), and Vmax and Km were obtained from the resulting regression coefficients.
| Duroquinone |
2,5-DCBQ |
|||
|---|---|---|---|---|
| Km | Vmax | Km | Vmax | |
| μm | μmol O2/mg Chl/h | μm | μmol O2/mg Chl/h | |
| Monomer | 85.5 (±6.6) | 1830 (±54.7) | 49.5 (±6.6) | 3870 (±167) |
| Dimer | 82.3 (±4.7) | 1570 (±35.8) | 50.3 (±11.8) | 4380 (±343) |