title: Short-term binding and hydrolysis of cyclic 3':5'-adenosine monophosphate by aggregating Dictyostelium cells.
abstract: Transient binding of cyclic AMP to aggregating cells of Dictyostelium discoideum was measured under cyclic GMP excess in order to inhibit cyclic AMP hydrolysis by cell-bound phosphodiesterase. Cyclic GMP extended the period of half-maximal cyclic AMP binding from less than 5 sec to 1-2 min. With the same time course as bound cyclic AMP was released from the cells, labeled 5'-AMP appeared in the medium. Specificity, kinetics, and developmental regulation suggest that the cyclic AMP-binding sites exposed in living cells are identical with receptor sites for the chemotactic response. The functioning of the cyclic AMP-receptor/phosphodiesterase system and its formal similarity with the synaptic acetylcholine-receptor/esterase system are discussed.
mesh_terms: D001665:Binding Sites; D002462:Cell Membrane / Q000201:enzymology; D002633:Chemotaxis; D002848:Chromatography, DEAE-Cellulose; D002850:Chromatography, Gel; D000242:Cyclic AMP / Q000378:metabolism*; D006868:Hydrolysis; D009235:Myxomycetes / Q000378:metabolism*; D010727:Phosphoric Diester Hydrolases / Q000378:metabolism
chemical_list: D000242:Cyclic AMP; D010727:Phosphoric Diester Hydrolases