Comparison of purine and pyrimidine metabolism in G1 and S phases of HeLa and Chinese hamster ovary cells

Abstract

Detailed quantitative studies of purine and pyrimidine metabolism in G1 and S phases of synchronized HeLa [human cervical carcinoma] and Chinese hamster ovary [CHO] cells were carried out. Concentrations of ribonucleoside triphosphates increased approximately in proportion to the increase in cell size as cells moved from G1 to S phase. Deoxyribonucleoside triphosphate concentrations were low in G1phase and increased 2.5- to 10-fold in S phase. Pathways and rates of metabolism of radioactive adenine, guanosine, deoxyadenosine, deoxyguanosine, uridine, cytidine, deoxyuridine, deoxycytidine, and thymidine were determined by measuring the incorporation of each precursor into individual acid-soluble nucleotides and RNA and DNA bases. Cell-cycle or size-dependent differences were detected in many of the parameters studied.