Catabolic pools in Escherichia coli.

Methods are described for measuring soluble pool magnitudes in steady-state or exponentially growing cultures, and for distinguishing between anabolic, catabolic and total metabolic pools within cells. These methods were applied to the measurement of pool magnitudes for several amino acids and other precursors in Escherichia coli THU. Our results support the independence of the magnitudes of total metabolic pools and growth rate in steady-state cultures. Our results also show that the total metabolic pool size is much larger than previously published estimates, which failed to include the contribution of catabolic pools. The average value of the total soluble material in exponential-phase cells is estimated to be 8 to 9% of the cell dry mass; pool values could be almost twice as large during midcycle because of the known increase in the magnitudes of protein and RNA precursor pool during the cell cycle.