Table 1.
Kinetic constants for the activation of fX derivatives by extrinsic and intrinsic Xase complexes
| Extrinsic Xase complex | Intrinsic Xase complex | |||||
| Km (nM) | kcat (nM/min/nM) | kcat/Km | Km (nM) | kcat (nM/min/nM) | kcat/Km | |
| WT | 75.8 ± 2.8 | 457.4 ± 5.5 | 6.0 | 51.6 ± 4.6 | 234.9 ± 6.4 | 4.6 |
| R71A | 59.6 ± 5.3 | 246.9 ± 7.0 | 4.1 | 55.0 ± 3.6 | 54.7 ± 1.1 | 1.0 |
| E74A | 107.2 ± 5.7 | 451.6 ± 8.5 | 4.2 | 80.6 ± 4.1 | 109.1 ± 1.9 | 1.4 |
| E76A | 91.4 ± 2.4 | 428.0 ± 4.2 | 4.7 | 49.2 ± 2.7 | 148.4 ± 2.4 | 3.0 |
| E77A | 100.1 ± 4.9 | 358.5 ± 6.5 | 3.6 | 54.8 ± 4.4 | 147.9 ± 3.7 | 2.7 |
The kinetic constants were determined from the concentration dependence of the activation of fX derivatives by either the extrinsic or the intrinsic Xase complex in TBS/Ca2+ at room temperature as described under Materials and Methods. All values are the average of at least two to three measurements ± standard errors.