Effect of high pressure oxygen on the steady state of cytochromes in rat-liver mitochondria

Abstract

1. The split-beam spectrophotometer was used to monitor changes in the steady state of cytochrome c and cytochromes a+a(3) during pressurization in pure oxygen. 2. High-pressure oxygen was found to cause oxidation of cytochrome c in rat-liver mitochondria, and of cytochromes a+a(3) at low pH. 3. No difference in these effects was found when various substrates were metabolized. 4. Lowering of pH markedly potentiated the high-pressure effect on the cytochromes. 5. Increased temperature and pressure hastened the reaction to high-pressure oxygen. 6. The oxidation of the cytochromes occurs on the substrate side of cytochrome c, probably at the dehydrogenase level, and the time-course of the reaction is compared with effects of oxygen toxicity in vivo.