Rapid assay for cyclic AMP and cyclic GMP phosphodiesterases.

A rapid highly sensitive assay for cyclic AMP phosphodiesterase has been devised. After a 5-min incubation, cyclic AMP is readily resolved from 5′-AMP, adenosine, and inosine by ion-exchange thin-layer chromatography on 1.3 × 6.5-cm strips of PEI-cellulose for 7 to 8 min. This procedure combines the accuracy of the standard paper chromatography assay (1) with the speed of ion-exchange resin techniques (2), while surmounting some of the major drawbacks of the other two methods (3). Since chromatography on PEI-cellulose efficiently resolves cyclic GMP, 5′-GMP, and guanosine, this methodology has also been adapted to the measurement of cyclic GMP hydrolysis.