Abstract
Since Skou (1) and Post et al. (2) reported, it has been well known that the active transport of ions across the cell membrane is closely related to the (Na+ + K+)-stimulated ATP-ase in the membrane. It is also accepted that mitochondria take up and extrude several kinds of ions from and into the surrounding medium (3-6). Relations between an ion transport and the ATPase activity in mitochondria have been studied by several workers (7-10). Carafoli et al. (8) suggested that ouabain-insensitive ATPase, which was associated with an ion transport, existed probably in the membrane of liver mitochondria. Ozawa et al. (11) reported that the ATPase of brain mitochondria was neither stimulated by sodium and potassium ions nor inhibited by ouabain. In the previous paper, the present authors (12) suggested a participation of ATPase on the ion transport in kidney cortex mitochondria.
Presently it was tried to make clear the properties of mitochondrial ATPase on ion transport system with special reference to the effects of sodium and potassium ions on enzyme activity.
