Table 1.
Steady‐state kinetic parameters of wild‐type and mutated maize L‐FNRs in the reactions of NADPH‐dependent cyt c reduction using Fd I at different NADPH concentrations. The values are mean ± SD of at least three independent measurements. ‘ND’ stands for ‘Not determined’.
| FNR | NADPH conc | ||||
|---|---|---|---|---|---|
| 50 μm | 250 μm | 500 μm | 1 mm | ||
| K m for Fd (μm) | Wild‐type | 3.5 ± 0.3 | 12 ± 3 | 22 ± 2.5 | 44 ± 10 |
| R235Q | 0.30 ± 0.02 | 1.5 ± 0.3 | 2.1 ± 0.7 | 5.0 ± 0.7 | |
| R244Q | 0.75 ± 0.09 | 2.1 ± 0.2 | 3.7 ± 0.5 | 6.9 ± 1.4 | |
| Y314S | 17 ± 1 | 13 ± 3.0 | 18 ± 2 | ND | |
| k cat (s−1) | Wild‐type | 52 ± 7 | 97 ± 12 | 210 ± 20 | 150 ± 10 |
| R235Q | 8.0 ± 1.3 | 32 ± 1 | 51 ± 6 | 53 ± 9 | |
| R244Q | 15 ± 1 | 49 ± 6 | 84 ± 8 | 70 ± 6 | |
| Y314S | 3.5 ± 0.4 | 3.6 ± 0.6 | 3.2 ± 0.5 | ND | |