Stepwise reduction of cytochromes b-562, b-566 and b-558 in rat liver mitochondria.
1. Addition of KCN to aerobic, rotenone-inhibited rat liver mitochondria with out addition of substrate caused reduction of cytochromes b-562 (having an alpha-band at 562 nm at room temperature), c + c1, and a + a3. The effect of KCN on cytochrome b-562 was reversed by pentachlorophenol, though the effect of KCN on cytochromes c+c1 and a+a3 was not reversed by this uncoupler.2. Addition of ATP to aerobic, rat liver mitochondria inhibited with 500 muM KCN under conditions were cytochromes b-562, c+c1 and a+a3 were reduced, caused reduction of cytochrome b-566. The absorbance spectrum of cytochrome b-566 had an alpha-band at 565.5 nm, a beta-band at 538 nm and a gamma-band at 431 nm, but no shoulder around 558 nm at room temperature. 3. Addition of succinate to rotenone-KCN-inhibited and ATP-treated rat liver mitochondria under conditions where cytochromes b-566, b-562, c+c1 and a+a3 were already fully reduced, caused reduction of cytochrome b-558 (having an alpha-band at 558 nm, a beta-band at 527 nm and a gamma-band at 426 nm at room temperature) after exhaustion of molecular oxygen in the reaction medium, without any contribution from a long-wavelength species (cytochrome b-566). 4. It was concluded that the 558-nm band is not a short-wavelength shoulder of cytochrome b-566, but is due to a different species from cytochrome b-566.
D000255:Adenosine Triphosphate / Q000494:pharmacology; D000332:Aerobiosis; D000818:Animals; D003486:Cyanides / Q000494:pharmacology; D003580:Cytochromes / Q000378:metabolism*; D007700:Kinetics; D008930:Mitochondria, Liver / Q000187:drug effects / Q000201:enzymology*; D009840:Oligomycins / Q000494:pharmacology; D010084:Oxidation-Reduction; D051381:Rats; D012402:Rotenone / Q000494:pharmacology; D013053:Spectrophotometry; D013997:Time Factors; D014475:Uncoupling Agents / Q000494:pharmacology
D003486:Cyanides; D003580:Cytochromes; D009840:Oligomycins; D014475:Uncoupling Agents; D012402:Rotenone; D000255:Adenosine Triphosphate