TABLE 5.
Kinetic parameters of α-ketoglutarate-dependent (R)-dichlorprop dioxygenase and α-ketoglutarate-dependent (S)-dichlorprop dioxygenase
| Substrate | Km (μM) | kcat (min−1) | kcat/Km (μM−1 min−1) |
|---|---|---|---|
| α-Ketoglutarate-dependent (R)-dichlorprop dioxygenase | |||
| (R)-Mecoprop (10-2,000 μM) | 98.8 ± 6.4 | 114.2 | 1.16 |
| (R)-Dichlorprop (50-2,000 μM) | 163.7 ± 13.5 | 170.1 | 1.04 |
| (R,S)-4-Chlorophenoxypropanoic acid (120-2,000 μM) | 262.4 ± 10.1 | 241.9 | 0.92 |
| O2 (0.02-1.0 mM) | NDa | ND | 0.64 |
| α-Ketoglutarate (7-1,900 μM) | 2.8 ± 0.8 | 135.6 | 48.82 |
| α-Ketoglutarate-dependent (S)-dichlorprop dioxygenase | |||
| (S)-Mecoprop (50-2,000 μM) | 132 ± 17.7 | 303.9 | 2.3 |
| (S)-Dichlorprop (120-2,000 μM) | 494.8 ± 43.9 | 284.6 | 0.58 |
| O2 (0.02-0.2 mM) | 159.32 | 116b | 0.75 |
| α-Ketoglutarate (8-1,000 μM) | 19.6 ± 2.5 | 229.7 | 11.72 |
a
ND, not determined.
b
The kinetic values for O2 were determined with material from two different SdpA purification batches, both of which were less active than the purification batches used for other kinetic experiments. However, the stoichiometry of the reaction was verified with material from a third purification batch (data not shown).