Effect of C6PS and C6PE on FVIIa amidolytic activity with or without rsTF
(A) The amidolytic activity of 100 nM FVIIa in a buffer containing 20 mM Tris, 150 mM NaCl, 5 mM Ca2+ and 0.6% PEG was assayed in the presence of 1 mM substrate Leu-PHG-Arg-pNA.AcOH and increasing concentrations of C6PS (•) and C6PE (○). Fitting the data to a single-site binding model yielded a Kd of 72 ± 17 with C6PS and 93 ± 14 µM with C6PE. (B) The amidolytic activity of 25 nM FVIIa in the presence of 100 nM rsTF in a buffer containing 50 mM Tris, 150 mM NaCl, 5 mM Ca2+ and 0.6% PEG was assayed in the presence of 1 mM substrate Leu-PHG-Arg-pNA.AcOH and increasing concentrations of C6PS (•) and C6PE (○). Fitting the data to the binding model explained in Figure 1 yielded a Kd of 68 ± 5 μM with C6PS and 83 ± 9 µM with C6PE.