Action of Calcium on Aerobic and Anaerobic Phosphorylation in Malignant and Certain Normal Tissues

Abstract

Oxidative phosphorylation by particles from rat liver with alpha-ketoglutarate as substrate, is completely inhibited by 0.0014 N Ca++ and only partially blocked by citrate at 4-fold concn. Mg exerts no effect on this system. When homogenates, particles, and supernates of rat liver, rat brain, and the Walker rat tumor 256 were subjected to the action of Ca, with hexose diphosphate and pyruvate as substrate, the max. inhibiting effect on P uptake of homogenates was observed with liver, an intermediate effect with brain, and a minimal effect with tumor. In all cases the P uptake, lactate production, and O2 uptake of supernates was entirely unaffected by Ca concns. up to 0.0028 N.