TABLE 3.
Kinetic constants for macromolecular substrate cleavage by prothrombinase
Steady-state kinetic constants were derived from initial velocity studies conducted with increasing concentrations of substrate. Concentrations of reaction components can be found under “Experimental Procedures.” The errors in the fitted constants represent ± 2 S.D. The data are representative of two to three independent measurements.
|
Prothrombin
|
Prethrombin-1
|
|||||
|---|---|---|---|---|---|---|
| Km | kcat | kcat/Km | Km | kcat | kcat/Km | |
| μm | min-1 | μm-1·s-1 | μm | min-1 | μm-1·s-1 | |
| PDFXa | 0.42 ± 0.02 | 2424 ± 54 | 96 | 5.4 ± 0.3 | 1088 ± 30 | 3.3 |
| rFXa | 0.35 ± 0.01 | 1937 ± 26 | 92 | 5.2 ± 0.4 | 1050 ± 35 | 3.4 |
| rFXaI16L | 0.31 ± 0.02 | 619 ± 14 | 33 | 5.7 ± 1.8 | 399 ± 10 | 1.2 |
| rFXaV17A | 0.47 ± 0.03 | 887 ± 26 | 31 | 6.9 ± 0.3 | 388 ± 8.9 | 0.9 |