Generation of factor Xa by factor VIIa in the presence of recombinant proteins. (A) Various concentrations of factor X were added to 1 nM factor VIIa, 5 μM PC/PS (molar ratio, 4:1), 5 mM CaCl₂, and Chromozym X substrate in the presence of 5 pM native TF (▪), sTF (▾), sTF-annV (•), or sTFAA-annV (○). Initial rates of substrate hydrolysis were measured as described in “Materials and methods,” to which the Michaelis-Menten equation was fitted. (B) Initial rates of factor Xa generation were measured in solutions containing 28 nM factor X, 5 mM CaCl₂, 1 nM factor VIIa, 0.347 μM PC/PS, and various concentrations of sTF (▾) or sTF-annV (•). Shown are the means ± SEM. (Most error bars are too small to be seen.)