title: [Calcium-dependent regulation of cardiac adenyl cyclase by calmodulin].
abstract: Calmodulin (CM) was found to activate adenylate cyclase (AC) in plasma membrane preparations of the rabbit heart in the presence of micromolar Ca2+ concentrations. CM action on the enzyme is terminated by trifluoperazine, troponin I and high Ma2 +/Ca2+ ratio. Isoproterenol in the presence of GTP, guanosine-5'-beta-gamma-imidotriphosphate[Cpp(NH)p] and sodium fluoride increases CM-dependent heart AC activity without changing the enzyme affinity to CM and Ca ions. CM has no effect on the convertion of regulatory N-protein into Gpp(NH)p-activated state. CM action on AC is revealed only if catalytic subunit forms a complex with regulatory N-protein. The conclusion was drawn that there is no distinct CM-dependent AC form in the heart, but the same catalytic subunit of the enzyme is regulated both by N-protein and CM. In the presence of Ca2+ and guanye nucleotides AC of the heart exists in the form of a complex: CM-catalytic subunit-N-protein.
mesh_terms: D000262:Adenylyl Cyclases / Q000378:metabolism*; D000818:Animals; D002118:Calcium / Q000502:physiology*; D002147:Calmodulin / Q000502:physiology*; D019204:GTP-Binding Proteins; D006160:Guanosine Triphosphate / Q000494:pharmacology; D006165:Guanylyl Imidodiphosphate / Q000494:pharmacology; D066298:In Vitro Techniques; D007545:Isoproterenol / Q000494:pharmacology; D008274:Magnesium / Q000502:physiology; D009206:Myocardium / Q000201:enzymology*; D011817:Rabbits; D011956:Receptors, Cell Surface / Q000502:physiology; D012508:Sarcolemma / Q000201:enzymology; D012969:Sodium Fluoride / Q000494:pharmacology
chemical_list: D002147:Calmodulin; D011956:Receptors, Cell Surface; D006165:Guanylyl Imidodiphosphate; D006160:Guanosine Triphosphate; D012969:Sodium Fluoride; D019204:GTP-Binding Proteins; D000262:Adenylyl Cyclases; D008274:Magnesium; D007545:Isoproterenol; D002118:Calcium
vernacular_title: Kal'tsiizavisimaia reguliatsiia adenilattsiklazy serdtsa kal'modulinom.