title: GTPase activity associates with the inhibitory GTP-binding regulatory component of adenylate cyclase purified from rat brain.
abstract: The inhibitory regulatory component of adenylate cyclase (Ni) was highly purified from rat brain synaptic membranes. A low Km GTPase activity was always associated with Ni through the purification, and the recovery of GTPase activity correlated well with that of Ni. Purified Ni was hardly ADP-ribosylated by islet-activating protein (IAP). A heat-labile factor in the fraction of the stimulative regulatory component (Ns) restored ADP-ribosylation and also activated the GTPase about 2-fold. NaF which was reported to interact with Ni markedly reduced GTPase activity. The purified Ni fraction inhibited adenylate cyclase only in the presence of a heat-stable factor found in the partially purified regulatory component. GTPase and inhibitory activities were weak in myelin which contained only a small amount of Ni. These findings support the view that GTPase activity is an intrinsic activity of Ni and some factors are necessary for the function of Ni.
mesh_terms: D000246:Adenosine Diphosphate Ribose / Q000378:metabolism; D037361:Adenylate Cyclase Toxin; D000262:Adenylyl Cyclases / Q000378:metabolism*; D000818:Animals; D001426:Bacterial Proteins / Q000494:pharmacology; D001427:Bacterial Toxins / Q000494:pharmacology; D001921:Brain / Q000201:enzymology*; D020558:GTP Phosphohydrolases / Q000378:metabolism*; D019204:GTP-Binding Proteins; D007700:Kinetics; D037342:Pertussis Toxin; D010744:Phosphoric Monoester Hydrolases / Q000378:metabolism*; D051381:Rats; D011956:Receptors, Cell Surface / Q000378:metabolism*; D013570:Synaptic Membranes / Q000201:enzymology; D010566:Virulence Factors, Bordetella
chemical_list: D037361:Adenylate Cyclase Toxin; D001426:Bacterial Proteins; D001427:Bacterial Toxins; D011956:Receptors, Cell Surface; D010566:Virulence Factors, Bordetella; D000246:Adenosine Diphosphate Ribose; D037342:Pertussis Toxin; D010744:Phosphoric Monoester Hydrolases; D020558:GTP Phosphohydrolases; D019204:GTP-Binding Proteins; D000262:Adenylyl Cyclases