Nucleotide metabolism in Ehrlich ascites carcinoma cells

Abstract

Incubation of Ehrlich ascites tumour cells with radioactive glucose leads to rapid labelling of the nucleotides of RNA. Most of the label ( > 90%) is associated with the ribose moiety and the extent of labelling of the CMP of RNA is less than one-tenth that of the other three nucleotides. When 32P 1 is used as a precursor the specific activities of the four nucleotides are quite similar. It is proposed that the interconversion of nucleoside and nucleotide plays a major role in the incorporation of radioactive phosphorus into RNA. Preliminary studies suggest that inhibition of uridine kinase by CTP may be important in regulating pyrimidine nucleotide levels and possibly nucleic acid synthesis.