Effect of aging on the oxidative phosphorylation pathway.

The proposed study was undertaken to investigate the effect of aging on control of the oxidative phosphorylation pathway. Flux control coefficients for adenine nucleotide translocase and cytochrome c oxidase were determined using the procedure of Groen et al. [J.

Ca2+ release from energetically coupled tumor mitochondria.

A Na+/Ca2+ exchange activity for Ca2+ efflux has been identified in isolated Ehrlich ascites tumor mitochondria. Further, under conditions favoring cycling of Ca2+ across the mitochondrial inner membrane, extramitochondrial [Ca2+] also was shown to be Na+-dependent. The Na+/Ca2+ exchange showed sigmoidal kinetics with a mean (+/-SD) [Na+] required for half maximal stimulation of Ca2+ efflux of 8.