Figure 2. Comparison of the optically detected pK_a values for Mb and Hb ferryl with pH-dependent kinetics of decay with or without exogenous substrates added.

The reactivity data points refer to reactions listed in text. Explanation of key captions: iso-P, isoprostane F₂ formation by Mb [36]; HPODE, HPODE consumption by Mb [30]; ascorbate+ferryl, rate of ferryl reduction by ascorbate; haemin, HPODE consumption by free haemin [28]; Mb, ascorbate turnover and Hb, ascorbate turnover, catalytic ascorbate and urate oxidation by Mb and Hb respectively in the presence of H₂O₂.