title: Purification and characterization of the extracellular cyclic AMP phosphodiesterase of Dictyostelium discoideum.
abstract: Extracellular phosphodiesterase for adenosine 3':5'-monophosphate [EC 3.1.4.17] was purified from the supernatant of aggregation phase culture of Dictyostelium discoideum, and two types (type I and type II) of the enzyme were found. The type I enzyme was not absorbed on DEAE-Sephacel at pH 8.5 and had an apparent molecular weight of about 67,000 daltons. In contrast, the type II enzyme was adsorbed on DEAE-Sephacel and had an apparent molecular weight of about 120,000 daltons. The Km values of the two types were similar (2-4 microM). Upon SDS polyacrylamide gel electrophoresis analyses, however, both types produced the same bands with molecular weights of 55,000 and 57,000, indicating that they are two different forms composed of common constituents. During the growth phase, the two types of the enzyme were present in culture supernatant in roughly equal amounts, but type II accumulated predominantly in the aggregation phase, suggesting that the ratio of activity of the two forms is under developmental control. Rabbit antiserum prepared against purified type II enzyme cross-reacted with type I as well as membrane-bound enzyme, indicating that the three classes of the enzyme possess some common sequence.
mesh_terms: D015105:3',5'-Cyclic-AMP Phosphodiesterases / Q000302:isolation & purification*; D000818:Animals; D055598:Chemical Phenomena; D002621:Chemistry; D004023:Dictyostelium / Q000201:enzymology*; D005110:Extracellular Space / Q000201:enzymology; D006863:Hydrogen-Ion Concentration; D007106:Immune Sera; D007120:Immunochemistry; D011817:Rabbits
chemical_list: D007106:Immune Sera; D015105:3',5'-Cyclic-AMP Phosphodiesterases