TABLE 3.
Kinetic parameters of substituted SorAB sulfite dehydrogenases, SDHY236F, SDHR55M, and SDHH57A
Square brackets denote values for which insufficient data points could be obtained due to the high sulfite concentrations needed to achieve saturating sulfite concentrations.
|
pH
|
Kinetic parameters
|
||
|---|---|---|---|
| Km(sulfite) | kcat | kcat/Km(sulfite) | |
| mm | s-1 | m-1 s-1 | |
| SDH Y236F | |||
| 6.0 | 0.004 ± 0.6 × 10-3 | 36.8 ± 1.5 | 8.42 × 106 |
| 6.5 | 0.007 ± 0.6 × 10-3 | 41.6 ± 0.8 | 5.60 × 106 |
| 7.0 | 0.026 ± 0.0032 | 51.8 ± 1.5 | 1.97 × 106 |
| 7.5 | 0.042 ± 0.0041 | 48.3 ± 1 | 1.14 × 106 |
| 8.0 | 0.114 ± 0.0135 | 53.4 ± 1.6 | 4.61 × 105 |
| 8.5 | 0.332 ± 0.0447 | 58.3 ± 2.4 | 1.73 × 105 |
| 9.0 | 1.155 ± 0.1166 | 64 ± 2 | 5.45 × 104 |
| 9.5 | 4.456 ± 0.6693 | 52.7 ± 3.5 | 1.16 × 104 |
| 10.0 | 15.487 ± 2.8 | 44.8 ± 4.7 | 2.84 × 103 |
| SDH R55M | |||
| 5.8 | 0.812 ± 0.114 | 70.5 ± 2.4 | 8.68 × 104 |
| 6.2 | 1.087 ± 0.26 | 64.0 ± 3.9 | 5.89 × 104 |
| 6.6 | 1.63 ± 0.39 | 64.0 ± 4.3 | 3.93 × 104 |
| 7.0 | 1.95 ± 0.49 | 66.3 ± 4.2 | 3.4 × 104 |
| 7.5 | 3.62 ± 0.57 | 68.3 ± 3.3 | 1.89 × 104 |
| 7.9 | 8.17 ± 1.37 | 73.4 ± 4.8 | 8.98 × 103 |
| 8.3 | [33.27 ± 7.5] | [109.88 ± 15.04] | [3.3 × 103] |
| SDH H57A | |||
| 6.0 | 0.667 ± 0.12 | 238.8 ± 16.5 | 3.58 × 105 |
| 6.5 | 0.29 ± 0.003 | 226.5 ± 7.6 | 7.82 × 105 |
| 7.0 | 0.189 ± 0.001 | 214.5 ± 3.7 | 1.13 × 106 |
| 7.5 | 0.22 ± 0.002 | 220.5 ± 5.6 | 1.01 × 106 |
| 8.0 | 0.27 ± 0.003 | 214.6 ± 6 | 7.99 × 105 |
| 8.5 | 0.452 ± 0.06 | 222.4 ± 9.9 | 4.92 × 105 |
| 9.0 | 1.46 ± 0.16 | 192.5 ± 7.5 | 1.32 × 105 |
| 9.5 | 12.2 ± 3.4 | 148.4 ± 25.8 | 1.22 × 104 |