Figure 3.

Clotting of fresh or coagulation factor-depleted plasmas in the presence of VaaSP-VX. (A) To fresh human plasma, VaaSP-VX was added at indicated concentrations and incubated at 37 °C for 10 min. The activated partial thromboplastin (aPTT) was then measured as described under Section 5: Materials and Methods. (B) To assess the plasma re-calcification time, the same procedure as in (A) was used, except the addition of the aPTT SA reagent was replaced by the addition of PBS. (C) To human plasma depleted in FVII, VaaSP-VX was added at the indicated concentrations. After 2 min of incubation at 37 °C, 25 mM CaCl₂ was added and the formation of fibrin clotting was observed by measuring the absorbance at 405 nm (A₄₀₅).