Table 1.
Equilibrium constants for GST-L–His-Ran bindinga
| Inhibitor | Mean value (±SD) |
||||
|---|---|---|---|---|---|
| kon (M−1 s−1) | koff (s−1) | KD (nM) | Ki (μM) | IC50 (mM) | |
| None | 1.01 (±0.01) × 105 | 3.39 (±0.54) × 10−4 | 3.25 (±0.63) | NA | NA |
| GDP, 10 μM | 2.33 (±0.06) × 104 | 4.98 (±0.36) × 10−4 | 22.0 (±1.4) | 1.73 (±0.11) | 1.0 (±0.2) |
| GTP, 10 μM | 1.79 (±0.01) × 104 | 8.81 (±0.07) × 10−4 | 48.8 (±0.2) | 0.714 (±0.003) | 2.5 (±0.1) |
a
On and off rates were determined through Langmuir fitting of normalized sensorgrams. KD was determined as the ratio of koff/kon when adjusted for the concentration of His-Ran in solution. Uncertainty was determined as the standard deviation of triplicate measurements. Significant figures were limited by the precision of protein concentrations. Ki was calculated using the equation Ki = [GXP]/[(KDGXP/KD) −1], where GXP represents either GDP or GTP. IC50 was calculated using the equation IC50 = Ki(1 + [Rancell]/KD). NA, not applicable.