FIGURE 4.

Effects of alanine mutation of 707-714 residues on FVIIIa reconstitution as measured by FXa generation assays. bA2 subunit was titrated in the presence of 1 nm A1/A3C1C2 dimer to reconstitute FVIIIa, followed by addition of 40 nm FIXa and 10 μm PS/PC/PE vesicles. Reactions were initiated with the addition of 300 nm FX. Initial rates were plotted as a function of A2 subunit concentration and fitted to a single-site ligand binding equation by nonlinear least squares regression. Assays were performed at least three times and mean ± S.D. are shown. Curves represent WT, (●), K707A (■), S709A (▴), S710A (♦), D712A (○), K713A (▵), and N714A (□).