Fig. 5.

Mitochondrial cytochrome reductions in response to different ROS molecules. Isolated liver mitochondria from young F344 rats were lysed in RIPA buffer containing GSH (1 mM) and sodium cyanide (NaCN, 5 μM), a cytochrome c oxidase inhibitor that prevents the reduced form from being re-oxidized. Mitochondria samples lysed in the presence of GSH were then treated with xanthine (2 mM) and xanthine oxidase (XO, 10 μM) and either (A) vehicle, (B) catalase (CAT, 1 mg/mL) to scavenge H₂O₂ or (C) Mn-TMPyP (40 and 80 μM) to scavenge superoxide anions. Visible absorbance was recorded from 500 to 660 nm. The reduced forms of cytochrome c and aa3 have absorbance maxima at 550 and 600 nm, respectively.