Apparent Kd for binding of FXa to FV mutants estimated in the prothrombinase assay
FV variant . | Kd, pM . | kcat, S-1 . | Km, nM . |
|---|---|---|---|
| WT FVa | 200 | 165 | 250 |
| Ala221Val | 200 | 160 | 250 |
FV variant . | Kd, pM . | kcat, S-1 . | Km, nM . |
|---|---|---|---|
| WT FVa | 200 | 165 | 250 |
| Ala221Val | 200 | 160 | 250 |
The apparent Kd's for the interaction between FXa and the different FV mutants were calculated by fitting the data shown in Figure 4A to an equation describing a single-site binding isotherm via nonlinear least squares regression analysis. Km values were calculated from data of Figure 4B fitted to the Michaelis-Menten equation. The kcat values were calculated from the absolute rate of maximal thrombin observed in the experiment presented in Figure 4B.