Participation of an intermediate of oxidative phosphorylation in ion accumulation by mitochondria.

Heart mitochondria accumulate massive amounts of Mg(++) and phosphate or Ca(++) and phosphate when incubated under appropriate conditions. Studies with inhibitors of respiration, oligomycin, and uncouplers of oxidative phosphorylation indicate that the energy necessary for these reactions may be provided either in the form of ATP in the absence of electron transport, or in the form of a high-energy intermediate of oxidative phosphorylation, which operates even though ATP is not produced.