Characterization of the oxygen probe pyrenebutyric acid in rabbit heart mitochondria

The fluorescence of pyrenebutyric acid is quenched by oxygen and the quenching is a linear function of the oxygen concentration. In addition, pyrenebutyric acid has been shown to be readily taken up by the cell with a partition coefficient of approx. 200. Results are presented on the effect of pyrenebutyric acid on oxidative metabolism in rabbit heart mitochondria. 1. Pyrenebutyric acid is readily taken up by heart mitochondria: 0.843 +/- 0.087 nmol pyrenebutyric acid taken up by Mr/mg dried weight. 2. Pyrenebutyric acid does not alter the steady-state redox levels (State 1, 2, 4 or 5) of any member of the respiratory chain. 3. Pyrenebutyric acid does not alter the response of cytochrome b, cytochrome c or NADH in the State 4-3-4 transition induced by the addition of ADP. Thus pyrenebutyric acid would appear to be non-toxic to oxidative metabolism.