Figure 3.

H₂O₂-derived degradation of cytochrome c. 15 μm cyt c was incubated in 10 mm PB, pH 7.4, either in the absence (dashed) or presence of H₂O₂ (straight lines; 75, 150, 300, 750, and 1500 μm) for 3 h at 37 °C. As shown in A, although in the absence of H₂O₂ an incubation time of 3 h did not result in significant spectral changes (compare gray and black dashed lines), incubation with H₂O₂ for 3 h led to a concentration-dependent decrease in the Soret band and the heme-derived bands beyond 510 nm. As shown in B, by continuously monitoring the loss of the Soret band an H₂O₂-concentration-dependent loss of the Soret band was observed, indicating a progressive loss of heme-containing cyt c. Averaged curves from three independent experiments are given.