Mutants of chinese hamster cells resistant to adenosine.

Chinese hamster cells do not grow in medium containing high concentrations of adenosine because pyrimidine biosynthesis is inhibited. Adenosine metabolism was examined in two mutant cell lines isolated on the basis of resistance to adenosine. One line was deficient in adenosine kinase suggesting that high intracellular AMP concentrations may block pyrimidine synthesis indirectly in wild type cells by inhibiting PRPP synthetase. Although no enzymatic defect could be identified in the other cell line, these cells inefficiently utilize adenosine supplied in the medium.