Table 2.
Kinetics of FXII activation
| FXII autoactivation (−HK) |
FXII activation by kallikrein | ||||
|---|---|---|---|---|---|
| Activating surface | Km | k cat | kcat/Km | initial rate (+HK) | initial rate (−HK) |
| μM | min−1 | × 103 M−1 s−1 | nM·min−1nM−1 | nM·min−1nM−1 | |
| dextran sulfate | 7.5a | 2.0a | 4.0a | 114 ± 14 | 257 ± 20 |
| Ni-NTA-liposomes | 2.6 ± 0.3 | 1.4 ± 0.2 | 8.7 ± 1.1 | 48 ± 5 | 471 ± 20 |
| NTA-liposomes | NAb | NA | NA | NA | 119 ± 20 |
| No surface | NA | NA | NA | NA | NA |
Data are mean ± SEM (n = 3).
a
Literature values from Tankersley and Finlayson.
b
NA, negligible activity.