Figure 1. Rates of ferryl formation measured by the reaction of H₂O₂ with the met forms of rHbA and rHbF.

The met forms of rHbA and rHbF (10 µM) were reacted with varying amounts of H₂O₂ in 20 mM sodium phosphate buffer, pH 7.2 at 37°C. (A) The spectral changes observed in the visible region for the conversion of met rHbF into the ferryl form on reaction with 1 mM H₂O₂. Spectra are shown every ~1 s of the reaction from t = 0 to 20 s. (B) A typical kinetic trace for the conversion of met rHbA into the ferryl form on reaction with 1 mM H₂O₂. (C). The observed rate constants for the reactions of rHbA and rHbF with varying concentrations of H₂O₂. For rHbA and rHbF, the k_obs.s⁻¹ value was calculated by fitting the kinetic traces to double exponential functions. Triangles = rHbA (open = fast, closed = slow), circles = rHbF (open = fast, closed = slow). Straight lines of best fit have been applied to the datasets.