STUDIES ON THE MODE OF ACTION OF DIPHTHERIA TOXIN. I. PHOSPHORYLATED INTERMEDIATES IN NORMAL AND INTOXICATED HELA CELLS.

Intracellular levels of ATP, GTP, and hexose phosphates have been determined in HeLa cells at intervals after exposure to saturating doses of diphtheria toxin. Toxin causes no significant change in the level of any of these phosphorylated intermediates either in the presence or absence of glucose over a period of at least 5 to 6 hours. It is concluded that the inhibition of protein synthesis which occurs in HeLa cells at about 2 hours after the addition of saturating doses of toxin, does not result from an effect of toxin on energy metabolism.