Fig. 2.

Mechanistic analysis of inactivation of myeloperoxidase by hydrogen peroxide. (A) Partition ratio for the inactivation of MPO by hydrogen peroxide. Residual hydrogen peroxide concentrations were measured at 60 min using the FOX assay when MPO reacted with increasing hydrogen peroxide concentrations at the constant hydrogen peroxide to protein ratio of 5000:1 in 50 mM phosphate buffer, pH 7.4, and 100 μM DTPA (same conditions as Fig. 1C). (B) Determination of kinetic parameters for the inactivation of MPO by H₂O₂. Half-times of inactivation, t_1/2, were determined from Fig. 1C and initial concentrations of hydrogen peroxide were used in the secondary plot.