Changes in quantitative oxygen uptake rate and redox state of Cytochromes as a function of normal, critical, and anoxic conditions

摘要

Isolated mitochondria were used to investigate quantitative oxygen uptake rate during oxidative phosphorylation. At the PO_2 of 70 mmHg the reaction was initiated. During the initial part of oxidative phosphorylation the turnover rate increased. The recorded PO_2 slope decayed linearly over time from 60 to about 10 mmHg, which is correlated to a constant oxygen uptake rate. Below 10 mmHg the PO_2 deviated from linearity indicating a decreasing O_2 uptake of mitochondria. No change in redox state of respiratory enzymes was observed. At very low PO_2 values the scattering of mitochondria decreased and finally at total anoxia a very fast drop of backscattered light intensity and a total reduction of cytochrome was observed.