PHOSPHATE-ACTIVATED GLUTAMINASE EXPRESSION DURING TUMOR-DEVELOPMENT

Changes in phosphate-activated glutaminase activities determined in in tact cells and isolated mitochondria have been followed during mouse E hrlich ascites carcinoma development. Glutaminase activities parallel the levels of poly(A)(+) RNAs encoding for the mitochondrial phosphate activated glutaminase. During the exponential growth phase, maximum a ctivity was observed and the relative abundance of glutaminase mRNA si gnificantly increased with regard to the stationary growth phase. The presented results show that tumor phosphate-activated glutaminase is s ubject to long-term regulation by differential gene expression.