Table 1. Kinetic constants for activity of TOP.
The results are expressed as the means±S.E.M., obtained from curve fitting a hyperbolic function to the initial rates at 8–9 different concentrations of substrate. Each individual substrate concentration was carried out in at least triplicate.
| MCA | mca-Bk | |||
|---|---|---|---|---|
| [Urea] (M) | kcat (s−1) | Km (μM) | kcat (s−1) | Km (μM) |
| 0 | 0.42±0.02 | 6.4±0.7 | 0.30±0.01 | 0.057±0.005 |
| 1.5 | 0.066±0.01 | 13.7±2.6 | 0.72±0.01 | 0.13±0.01 |
| 2.5 | 0.010±0.001 | 9.4±1.1 | 0.91±0.01 | 0.48±0.02 |
| 3.5 | – | – | 1.07±0.06 | 1.27±0.16 |