FIGURE 3.

Effect of AA and GDP on proton leak kinetics of skeletal muscle mitochondria isolated from wild-type (A) and UCP3-null (B) mice. The proton leak rate (expressed as the respiration rate that drives the leak) is plotted as a function of membrane potential and was detected in the presence of CAT. The membrane potential was varied by titration with malonate. The insets show the -fold proton leak induction (evaluated by measuring the increase in the respiration rate at the maximal common membrane potential (144 mV)). Error bars labeled with different letters are significantly different (p < 0.05). Black circles and black bars, mitochondria with no addition; white circles and white bars, mitochondria with AA; gray circles and gray bars, mitochondria with AA plus GDP. Values are means ± S.E. of four independent experiments, each one performed in duplicate. prot, protein.