Figure 6.

Reaction of WT KpDyP and D143A Compound I with thiocyanate and serotonin. A and C, reaction of WT Compound I with thiocyanate (A) and serotonin (C) at pH 7.0, followed by the sequential stopped-flow mode. Compound I (green spectrum) was preformed by mixing 2 μm ferric KpDyP with 4 μm H₂O₂ in 50 mm phosphate buffer, pH 7.0. After a 100-ms delay time, 1 mm thiocyanate (A) or 50 μm serotonin (C) was added. B and D, reaction of D143A Compound I with thiocyanate (B) and serotonin (D) at pH 7.0, followed by the sequential stopped-flow mode. Compound I (green spectrum) was preformed by mixing 2 μm ferric D143A with 1 mm μm H₂O₂ in 50 mm phosphate buffer, pH 7.0. After a 3000-ms delay time, 10 μm thiocyanate (A) or 1 mm serotonin (C) was added. Ferric spectra are shown in black, and oxoiron(IV)-type Compound II spectra are shown in orange. Relevant absorption maxima and time points of selection of the spectra are depicted.