Nucleotide metabolism in Ehrlich ascites cells.

Studies have shown that about 95 per cent of the radioactivity incorporated from glucose-U-14C into RNA nucleotides is found in the ribose moiety of each nucleotide. The radiospecific activity of the ribose moieties of guanine and uracil were the highest; that of adenine was somewhat lower, while the specific activity of the ribose of cytosine was about ten times lower than the above three. It has been shown that the specific activities of the various nucleotides of RNA are a reflection of the labelling of the corresponding nucleotides in the acid-soluble fraction. These results are discussed in relation to the comparative utilization of purine and pyrimidine bases by radioactive ribose-phosphate for the formation of the labelled nucleotides of RNA