Table 1. Steady-State and Pre-Steady-State Kinetic Parameters for MtATP-PRTa.
| parameter | best fit | equation |
|---|---|---|
| Vmax (s–1) | 0.31 ± 0.01 | 1 |
| Km,ATP (μM) | 263 ± 63 | 1 |
| Km,PRPP (μM) | 49 ± 6 | 1 |
| Kact,Mg2+ (μM) | 1900 ± 600 | 2 |
| Ki,Mg2+ (μM) | 23000 ± 900 | 2 |
| IC50,l-histidine (μM) | 33 ± 3 | 3 |
| Amax (μM) | 7.8 ± 0.3 | 8 |
| Kd,ATPapp (μM) | 47.2 ± 10.3 | 8 |
| Kburst (s–1) | 0.67 ± 0.02 | 9 |
| Kd,l-histidine (μM) | 27.9 ± 3.2 | 10 |
| kon,l-histidine(M–1 s–1) | 4885 ± 717 | 11 |
| koff,l-histidine (s–1) | 0.95 ± 0.03 | 11 |
a
Assays performed in 50 mM buffer, containing MgCl2 and KCl, at the specified values, and 25 °C. See Materials and Methods for the buffers and concentrations of substrates, metals, and l-histidine.