Mitochondria respiring on succinate are not irreversibly depolarized.

<p>O₂ flux in mitochondria respiring as in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0154982#pone.0154982.g002" target="_blank">Fig 2B</a> on 5 mM succinate could be rescued by addition of 5 mM pyruvate (panel A), 5 μM rotenone (panel B), or 2 mM ascorbate + 0.5 mM N,N,N',N'-Tetramethyl-p-phenylenediamine dihydrochloride (TMPD) to provide electrons directly to complex IV (panel C); indicating that the functional status of the organelles was preserved. O₂ flux could not be rescued by adding additional succinate to a final concentration of 10 mM (panel D). Solid lines indicate O₂ flux prior to addition of the compound indicated. Dotted lines indicate O₂ flux after addition. Each panel is representative of 2–3 repetitions.