Figure 3.

Sulfide concentration-dependent inhibition of MPO peroxidase activity. (A) Representative curve for percentage of inhibition of MPO peroxidase activity at 30 µM H₂O₂ as a function of added sulfide concentration. (B) Effect of H₂O₂ concentration on the sulfide-mediated 50% inhibition on MPO peroxidase activity. Data shown are means ± SD of three independent experiments. (C) Representative absorbance changes recorded at 652 nm for the peroxidase activity of MPO in the absence (blue line) and presence of 1 µM sulfide (red line). MPO peroxidase activity was measured by the TMB assay at 6 nM MPO.