Table 3.
Kinetic constants for prothrombin activation by fXa derivatives assembled into the prothrombinase complex
| Km (nM) | kcat (nM/min/nM) | Kd(app) (fVa, nM) | |
| WT | 51.6 ± 2.5 | 1096.4 ± 13.4 | 2.1 ± 0.3 |
| R71A | 85.6 ± 14.7 | 1434.3 ± 70.1 | 1.5 ± 0.2 |
| E74A | 56.7 ± 3.4 | 1205.9 ± 16.8 | 1.7 ± 0.3 |
| E76A | 52.4 ± 5.5 | 1241.1 ± 29.3 | 2.9 ± 0.3 |
| E77A | 62.9 ± 3.9 | 1510.0 ± 22.3 | 3.3 ± 0.6 |
The kinetic constants were determined from the concentration dependence of prothrombin activation by fXa derivatives in the prothrombinase 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.