G protein beta gamma-subunits inhibit purified adenylate cyclase independent of the activation by Ca2+ and calmodulin.
Adenylate cyclase purified by affinity chromatography was activated about 2.5-fold in a Ca(2+)- and calmodulin-dependent fashion. G protein beta gamma-subunits, an inhibitor in the receptor-mediated inhibition of adenylate cyclase, inhibited the purified cyclase by more than 80%. The extent of beta gamma-induced inhibition was not affected by the activation with Ca2+ and calmodulin. Moreover, the prior addition of the beta gamma-subunits to the cyclase did not prevent the subsequent activation of the enzyme by Ca2+ and calmodulin. We conclude that the beta gamma-subunits inhibit adenylate cyclase activity in a calmodulin-independent mode.
Enomoto
K
K
Department of Pharmacology, Saga Medical School, Japan.
Hayama
K
K
Takano
M
M
Asakawa
T
T
D000067956:Adenylyl Cyclase Inhibitors; D000818:Animals; D001711:Biotransformation / Q000187:drug effects / Q000502:physiology; D001923:Brain Chemistry / Q000187:drug effects; D002118:Calcium / Q000378:metabolism / Q000494:pharmacology*; D002147:Calmodulin / Q000378:metabolism / Q000494:pharmacology*; D002846:Chromatography, Affinity; D004591:Electrophoresis, Polyacrylamide Gel; D019204:GTP-Binding Proteins / Q000737:chemistry* / Q000302:isolation & purification; D051381:Rats; D013552:Swine
D000067956:Adenylyl Cyclase Inhibitors; D002147:Calmodulin; D019204:GTP-Binding Proteins; D002118:Calcium