Microcompartmentation of cAMP in wild-type and memory-mutant dunce strains of Drosophila melanogaster

The "enzyme-probe" method [Solti M, Friedrich P: Eur J Biochem 95:551, 1979] has been applied to characterize the cyclic AMP pool in wild-type Canton-S and memory-mutant dunceM11 strains of Drosophila melanogaster. The kinetics of cyclic AMP breakdown in whole fly homogenates by endogenous cyclic nucleotide phosphodiesterase(s) indicate that the cyclic AMP pool is divided into free and bound fractions. The bound fraction in Canton-S and dunceM11 is 0.5 and 1.5 pmole/mg fly, respectively. Considering the total cyclic AMP content of the two strains, 1.6 and 10 pmole/mg fly, respectively, we conclude that the bulk of excess cyclic AMP in the mutant is free nucleotide.