Figure 3. Kinetics of H₂O₂ generation by recombinant human microsomal enzymes.

Assays mixes were prepared as described in the legend to Figure 2. Experiments were performed with a mixture of human drug metabolizing cytochrome P450’s coexpressed with human NADPH-cytochrome P450 reductase. Panel A. Continuous recording of H₂O₂ generation by human microsomal enzymes. Each well contained 10 μg/well (12 Units of NADPH-cytochrome P450 reductase, 1.5 pmol cytochrome P450) of protein. The data are the mean ± SD of three separate experiments in duplicate. Panel B. H₂O₂ generation by recombinant human microsomal enzymes at fixed time points. The data are the mean ± SD of two experiments with each microsomal protein concentration analyzed in triplicate. The dashed lines connecting the tops of the bars were generated by GraphPad Prism and were used for calculation of absolute rates of H₂O₂ production.