Effect of caffeine on nucleotide pools in Escherichia coli

The influence of caffeine on the intracellular concentration of various nucleoside triphosphates in addition do dTMP and dTDP, in Escherichia coli has been investigated. For most of the nucleoside triphosphates the presence of 10 mM caffeine in the medium resulted in a small increase in pool size 5 min after addition, followed by a slow decrease to the initial concentration. In the case of dTTP, however, the pool size reached a maximum, 2-fold higher than the initial value, 30 min after caffeine addition. This increase in dTTP level is probably due to an effect of caffeine on the DNA synthesis process and synthesis of dTDP-sugars.