FIGURE 2.

FX activation by FIXa in the presence of recombinant FVIII variants. Activation of FX was assessed by increasing concentration of FIXa (0–16 nm) in the presence of phospholipids, Ca²⁺ ions, and 0.3 nm FVIII WT and variants thereof as described under “Experimental Procedures.” Shown is the amount of FXa generated per minute for FVIII WT (circles), K1967I (triangles), K1967A (squares), and K1968A (diamonds). Data represent mean ± S.D. (error bars) of at least three independent experiments.