Figure 9

APC Inactivation of FVa in the Presence of Prothrombin and Saturating Levels of FXa. Empirical: FVa (20 nM) was pre-incubated with 30 nM active site blocked FXa (FXa*) and prothrombin (1.4 μM) at 37°C. The reaction was initiated with 2.0 nM (red circles) or 20.0 nM (blue circles) APC. A representative Western blot from an empirical experiment using 2.0 nM APC is shown in Panel A. Densitometric analysis of normalized measurements of the FVa^HC are presented in Panel B. Data points are the averages ± S.D. of either 4 or 3 experiments for inactivation studies conducted with either 2.0 or 20.0 nM APC, respectively. Mathematical: Simulated time courses (2.0 nM APC – red lines; 20.0 nM APC – blue lines) were generated with the assumption of limited binding sites, resulting in an effective APC concentration of 11 % (solid line) is shown.