Concentration dependence of FGF-1, -2, -4, -6 binding to α₂M and α₂M*.

A total of 15 ng ¹²⁵I–FGF-1 (A), ¹²⁵I–FGF-2 (B), ¹²⁵I–FGF-4 (C), or ¹²⁵I–FGF-6 (D) was incubated with varying concentrations of α₂M (●) or α₂M* (▪) for 2 hours at 37°C followed by nondenaturing pore-limit electrophoresis. Radioactivity was quantified on a Phosphorimager and represented by arbitrary units (AU). Binding and lines that represent the best least square fit (R² > 0.95) are plotted in the figure. The data are representative of 3 (FGF-1 and FGF-6) or 4 (FGF-2 and FGF-4) experiments. Table 1 contains a summary of theK_d values derived from these binding experiments.