PH-jump-induced ADP phosphorylation in mitochondria

Mitochondria, uncoupled by aging or by freeze-thaw treatment, are able to synthesize ATP from ADP and Pi after a fast increase (but not decrease) in the external pH. The maximal ATP yield (approx. 2.5 ATP molecules/electron-transport chain per pH jump) can be obtained under the following conditions: (1) the pH change during the jump must exceed 0.7 pH units; (2) in the course of this change, the pH of the mitochondrial suspension must cross the pH 8.1-8.3 value. This pH-jump-induced ATP synthesis is completely inhibited by oligomycin.