KINETICS OF SYNTHESIS AND UTILIZATION OF ADENOSINE TRIPHOSPHATE BY INTACT CELLS OF RHODOSPIRILLUM RUBRUM

The kinetics of formation then disappearance of adenosine triphosphate in intact adenosine triphosphate starved cells of Rhodospirillum rubrum were followed after initiation and cessation of illumination or oxygenation or a combination of these. Samples of bacteria were collected from a flow apparatus under various conditions into HClO4 and the adenosine triphosphate level of the supernatant samples was measured by the luciferin-luciferase method. Adenosine triphosphate synthesis on illumination of anaerobic bacteria showed an initial rate of 0.33 nmole sec-1 per mg dry weight that was independent of temperature between 4 and 37°. The maximal rate following oxygenation at 22° was around 0.17 nmole sec-1 per mg dry weight and this varied with temperature. The initial rate on illumination in the presence of O2 was similar to that seen on illumination of anaerobic cells. The level of adenosine triphosphate attained on illumination was higher than that reached on oxygenation, but illumination following oxygenation brought the level to the same as that attained on anaerobic illumination. The data support the postulate of two separate and probably independent electron transport phosphorylating systems. © 1969, American Chemical Society. All rights reserved.