Comparison of three kinetic curves for PSF association under different experimental conditions. A, apoPSF mixed with Fe2+ aerobically. B, apoPSF mixed with Fe2+ anaerobically. C, apoPSF mixed with Fe3+ aerobically. The curve represents an average of six experimental measurements. Condition: [apoPSF] = 0.5 μm in 100 mm Mops (pH 7.0), 48 μm FeSO4 or FeCl3, 25 °C.