Fig. 4.
The effect of F.VIIIa on the activation of human factor X.
Human F.X (600 nM) was incubated with 0.3 nM of F.IXa (closed circles) or 0.3 nM of plasmin-digested F.IX (open circles) in the presence of various concentrations of human F.VIIIa in TBS (tris buffered saline), pH 7.4 containing 0.1% BSA/5mM CaCl2and 30 mM of PCPS vesicles for 10 minutes at 37°C. The initial rate of cleavage of the chromogenic substrate S-2222 (0.4 mM final concentration) by human F.Xa generated is shown after determination of the F.Xa activity levels in the reactions with a standard curve constructed with known amounts of purified human F.Xa.
