Patterns of Synthesis of Thymidine Triphosphate and Other Deoxyribonucleoside Triphosphates in Mouse Liver and in Mouse Ascites Hepatoma

Summary

Patterns of synthesis of deoxyribonucleoside triphosphates in broken cell preparations of mouse liver and mouse ascites hepatoma were determined from the kinetics of conversion of deoxyribonucleotides labeled with C¹⁴ or P³². In the hepatoma, deoxythymidylate (TMP), deoxyguanylate (dGMP), and deoxyadenylate (dAMP) were extensively phosphorylated, but synthesis of deoxycytidine triphosphate (dCTP) was inhibited. In mouse liver, all the deoxyribonucleotides except TMP were actively phosphorylated, but in every case dephosphorylation reactions eventually set in. The synthesis of thymidine triphosphate (TTP) in mouse liver homogenate was largely prevented. The kinetics of TMP phosphorylation in mouse liver homogenate indicate that the relative lack of thymidine triphosphate synthesis in liver is not entirely due to a deficiency of enzyme but to other factors suppressing synthesis.