title: Agar plate screening procedure for cyclic adenosine 3',5'-monophosphate and inhibitors of cyclic nucleotide phosphodiesterase.
abstract: A procedure is described for the semiquantitative measurement of cyclic adenosine 3',5'-monophosphate (cAMP) and detection of inhibitors of cAMP phosphodiesterase by an agar plate test. The assay organism was an adenyl cyclase-deficient mutant derived from Escherichia coli HfrH. In the presence of an acid base indicator, acid production from barbohydrate metabolism was observed as a yellow zone around filter paper disks containing cAMP. Since yellow zone formation reflects the presence of cAMP, a phosphodiesterase inhibitor can be detected indirectly by the presence of a yellow zone on assay plates from a reaction mixture of an inhibitor, phosphodiesterase, and cAMP. Three known cyclic nucleotide phosphodiesterase inhibitors were active against beef brain phosphodiesterase in this system.
mesh_terms: D000262:Adenylyl Cyclases / Q000235:genetics; D000362:Agar; D001431:Bacteriological Techniques; D002110:Caffeine / Q000032:analysis; D000242:Cyclic AMP / Q000032:analysis* / Q000378:metabolism; D004926:Escherichia coli / Q000201:enzymology / Q000235:genetics / Q000378:metabolism; D005285:Fermentation; D005690:Galactose / Q000378:metabolism; D009154:Mutation; D010208:Papaverine / Q000032:analysis; D010726:Phosphodiesterase Inhibitors / Q000032:analysis*; D010727:Phosphoric Diester Hydrolases / Q000378:metabolism; D013806:Theophylline / Q000032:analysis
chemical_list: D010726:Phosphodiesterase Inhibitors; D002110:Caffeine; D000362:Agar; D013806:Theophylline; D010208:Papaverine; D000242:Cyclic AMP; D010727:Phosphoric Diester Hydrolases; D000262:Adenylyl Cyclases; D005690:Galactose