Glutamine metabolism in Ehrlich ascites-carcinoma cells

Abstract

The oxidation of glutamine in Ehrlich ascites-carcinoma cells proceeds through a-oxoglutarate and other intermediates of the tricarboxylic acid cycle. In cells lacking sufficient suitable precursors of acetyl-coenzyme A, the oxidation of glutamine results in the formation of aspartic acid. In the presence of substances giving rise to acetyl-coenzyme A, the rate of oxidation of glutamine is decreased, but the extent of oxidation is increased. The rate of glutamine oxidation is increased by sodium hydrogen carbonate and a-oxo acids. The incorporation of amino acids into proteins is inhibited under anaerobic conditions by pyruvate, oxaloacetate and phenylpyruvate. This inhibition is reversed specifically by glutamine. The incorporation of amino acids into proteins is inhibited under aerobic conditions by phenylpyruvate, and this inhibition is reversed by glutamine, pyruvate, oxaloacetate and glucose. Glutamine may serve as a source of energy under certain circumstances for the incorporation of amino acids into proteins by these cells.