The rate of turnover of the adenosine triphosphate pool of Escherichia coli growing aerobically in simple defined media.

Abstract

1. Methods are described for measuring the ATP pool in batch cultures of bacteria and of computing the rate of ATP synthesis from the rates of oxygen consumption and substrate utilisation. 2. The ATP pool of Escherichia coli (ML 308) growing aerobically at the expense of a variety of single carbon sources falls within the range 4.5–7.5 μmoles/g dry wt of cells. On any given compound the pool is constant during logarithmic growth. There is no simple relationship between growth rate and the size of the ATP pool. 3. The rate of synthesis of ATP is also constant during logarithmic growth and falls within the range 1.7–2.4 mmoles/g dry wt/min, assuming a P/2e ratio of 3. 4. During logarithmic growth the rate of turnover of the ATP pool falls within the range 250–450 times min-1. 5. Alterations in rate of growth and ATP synthesis occur simultaneously. These changes can be large and rapid (e.g. on exhaustion of a limiting nutrient) but are not reflected in the rate of change of the ATP pool which is much slower.