Inhibition of postoxidative calcium release in corn mitochondria by inorganic phosphate.

Respiration drives the accumulation of a small amount of calcium in corn (Zea mays L.) mitochondria, and this calcium is released when respiration ceases. A postenergized addition of phosphate leads to phosphate uptake and enhaced calcium retention. Oligomycin, KCN, 2,4-dinitrophenol, or mersalyl are without effect on the phosphate-induced calcium retention. Addition of phosphate also inhibits the release of endogenous phosphate which normally accompanies the calcium. It is suggested that passive phosphate uptake retards the release of endogenous phosphate which is complexed with the calcium.