In the mitochondrial matrix there are insoluble, osmotically inactive complexes that maintain constant pH and calcium concentration. In the present paper we examine the properties of insoluble calcium and magnesium salts, namely phosphates, carbonates and polyphosphates which might play this role. We find that non-stoichiometric, magnesium-rich carbonated apatite, with very low crystallinity, precipitates in the matrix under physiological conditions. Precipitated salt acts as pH buffer, and hence can contribute in maintaining ATP production in ischemic conditions, delaying irreversible damages to heart and brain cells after stroke.
Keywords: ATP production; calcium carbonates; calcium phosphates; calcium polyphosphates; hypoxia; ischemia; mitochondrion; preconditioning.