The Effect of Azide on Phosphoryla’iion Accompanying Electron Transport and Glycolysis*

The dissociation of respiration from synthetic processes by azide was shown by studies of Clifton in 1937 (1) and by the results of subsequent investigations (24). Hotchkiss in 1944 made the significant observation that, although bacterial respiration was enhanced by azide, inorganic orthophosphate (Pi) uptake was decreased (5). The ability of azide to uncouple oxidation of substrates from net adenosinetriphosphate (ATP) synthesis in intact cells and cell-free preparations has been well established; present evidence suggests that the uncoupling action of azide, like that of 2,4-dinitrophenol, is on the electron transport between reduced coenzymes and oxygen (6-9). The uncoupling would result if a phosphorylated intermediate were rendered unstable or if the initial uptake of Pi did not occur although electron transfer continued. Experiments labeled with Pi labeled with P32 and 018 which favor the latter possibility are presented in this paper. A second objective was to examine the relation of azide to phosphorylations accompanying anaerobic glycolysis. Data obtained by Spiegelman, Kamen, and Sussman have been interpreted as showing that azide dissociates anaerobic glycolysis from ATP synthesis (3). This suggestion, which has been accepted in more recent publications (10, II), is considered untenable in view of the experimental results presented herein.