Mitochondria with impaired phosphate transport: 32P uptake studies

Rat liver mitochondria which have been exposed to 0.15 M NaC1 at 35 degrees C for 15 min subsequently take up 32Pi from an external medium only to about 5% of the extent of uptake by control mitochondria. The volume into which 32Pi distributes in a pellet of such "aged" mitochondia is less than that available to 3H2O but is greater than that available to [3H]sucrose. Mitochondria treated in this manner cannot therefore accumulate Pi although limited penetration of the inner membrane can occur. These results confirm earlier findings by indirect methods (Williams, G. R. & Orr, J. L.: Dynamics of energy-transducing membranes (Ernster, L., Estabrook, R. W. & Slater, E. C., eds), Elsevier Scientific Publishing Company, Amsterdam, Netherlands, pp. 497-508 (1974).