Relative importance of alternative pathways of purine nucleotide biosynthesis in Ehrlich ascites tumor cells in vivo.

Several alternative pathways of purine nucleotide synthesis coexist in cells and the relative importance of each pathway for maintaining purine nucleotide concentrations in cells have been studied. Specific inhibitors were used to block these synthetic routes in Ehrlich ascites tumor cells in vivo and the effect of inhibiting each pathway was evaluated by measuring intracellular purine nucleotide concentrations by high-speed liquid chromatography. The results of this study indicate that adenosine triphosphate and guanosine triphosphate concentrations of Ehrlich ascites tumor cells are maintained primarily by purine biosynthesis de novo although other pathways do make significant contributions.