Figure 3

Alternative pathway activity. Antimycin A-insensitive oxidation of NADPH, NADH and succinate was measured to oxygen in the presence of DTT and pyruvate to assure maximum rates. Respiratory chain activities are displayed as percentage of control activity in each experiment. Control activities were: 12, 52 and 59 nmol NADPH min^-1 mg^-1; 25, 40 and 57 nmol NADH min^-1 mg^-1; or 60 and 52 nmol succinate min^-1 mg^-1 in the independent experiments. Rates of succinate oxidation were corrected for a small rate remaining after addition of antimycin A and salicylhydroxamic acid; 3–6 and 7–10 nmol O₂ min^-1 mg^-1 for control/A3, and A10/A30, respectively. Samples and error bars are denoted as for Fig. 1, where the corresponding rates for total respiration (cytochrome path plus alternative path) are presented.