Cellular metabolic control by chemical modification of cell membrane

Various reagents used in the chemical modification of amino- and carboxy-groups of proteins, and of carbohydrates of glycoproteins and glycolipids, inhibit respiration in ascites tumor cells concomitant with release of potassium ion from those cells. The respiratory activity of washed ascites tumor cells is increased by exogenous addition of potassium ion. The lowered respiratory control index as well as oxidative phosphorylation of aged mitochondria are restored upon increasing the potassium concentration of the incubation mixture in the presence of respiratory substrates. The data suggest that the potassium ion level of cells is changed by modifying physicochemical properties of membrane components and that cellular energy metabolism is regulated by intracellular potassium ion concentration.