The time-course of the synthesis of adenosine triphosphate in Ehrlich ascites-tumour cells, and the effect of 2,4-dinitrophenol.

1. In Ehrlich ascites-tumour cells kept in nitrogen at 20 degrees for 20-30min., the ATP concentration falls from about 15mumoles/g. dry wt. to 2-3mumoles/g. dry wt. 2. If oxygen is admitted to such cells, the ATP concentration rises again in 1-2min. to about 15mumoles/g. dry wt. 3. If glucose is added, in nitrogen, there is a slower increase in ATP concentration to about 6mumoles/g. dry wt., followed by a fall and then by a still slower rise. 4. With glucose and oxygen, the ATP concentration rises rapidly in 1min. to about 8mumoles/g. dry wt., then falls, and finally increases slowly to reach 15mumoles/g. dry wt. in 2hr. 5. 2,4-Dinitrophenol (0.3mm) has little effect on these processes. 6. At 1.0mm, 2,4-dinitrophenol completely inhibits the ATP synthesis dependent on the endogenous respiration, while leaving that in the presence of glucose only a little impaired in rate, and considerably greater in magnitude. 7. ATP synthesis in the presence of glucose and 1.0mm-2,4-dinitrophenol is about three times as fast in oxygen as in nitrogen.