Cyclic 3':5'-adenosine monophosphate in Escherichia coli during transient and catabolite repression

Cyclic AMP concentrations were low for an adenylate cyclase-deficient mutant (cya(-)) and abnormally high for a catabolite receptor protein-deficient mutant (crp(-)). A fall in cellular cAMP concentration was always found when cells were subjected to transient repression. No consistent correlations were observed between catabolite repression and cellular cAMP levels.