Degradation of the heme:HugZ complex in the presence of NADPH-cytochrome P450 reductase and ascorbic acid. (A) Degradation of hemin using recombinant human NADPH-cytochrome P450 reductase as the reductant. Arrows indicate the positions and directions of absorbance change with time. (B) Degradation of hemin using ascorbate as the reductant. The arrow indicates changes in absorption with time. The data are representative of triplicate independent spectrophotometric analyses.