Second-order rate constants (kon) of FXa or thrombin inhibition by pAT and AT variants in the presence of indicated heparin derivative.
| Antithrombin . | kon (M−1.s−1) ± SEM . | |
|---|---|---|
| FXa + fondaparinux . | Thrombin + UFH . | |
| pAT | (1.67 ± 0.11) × 105 | (1.02 ± 0.09) × 107 |
| AT-N135Q | (2.20 ± 0.07) × 105 | (1.38 ± 0.16) × 107 |
| AT-N135Q-Pro394 | 32.6 ± 4.4 | 15.2 ± 2.5 |
| Antithrombin . | kon (M−1.s−1) ± SEM . | |
|---|---|---|
| FXa + fondaparinux . | Thrombin + UFH . | |
| pAT | (1.67 ± 0.11) × 105 | (1.02 ± 0.09) × 107 |
| AT-N135Q | (2.20 ± 0.07) × 105 | (1.38 ± 0.16) × 107 |
| AT-N135Q-Pro394 | 32.6 ± 4.4 | 15.2 ± 2.5 |
Fast inhibition rate constants (kon > 104 M−1.s−1) were estimated in a continuous assay, whereas slow inhibition rate constants (kon < 104 M−1.s−1) were estimated in a discontinuous assay as described in lines 1 and 2. Errors represented the SEM from 2 or more experiments.
AT indicates antithrombin; FXa, factor Xa; pAT, plasma AT; and UFH, unfractionated heparin.