Measurement of cyclic 3',5'-adenosine monophosphate synthesis in growing Escherichia coli.

The net synthesis of cAMP by an adenine auxotroph of $\text{Escherichia coli}$ was measured by assaying the incorporation of tritium from [³H]-adenine into cyclic [³H] AMP during exponential growth. Synthesis of cAMP ceased abruptly when glucose was added to cells growing in glycerol and then recovered to an intermediate rate of synthesis after 0.5–1.0 generation. Cyclic AMP appeared to be synthesized from a precursor pool that turned over more rapidly than total cellular ATP. The rates of cAMP synthesis measured by this technique are compatible with the cellular levels of cAMP previously measured in this strain(3).