G Protein βγ-Subunits Inhibit Purified Adenylate Cyclase Independent of the Activation by Ca2+ and Calmodulin

[摘要] References(12)Cited-By(1)Adenylate cyclase purified by affinity chromatography was activated about 2.5-fold in a Ca2+- and calmodulin-dependent fashion. G protein βγ-subunits, an inhibitor in the receptor-mediated inhibition of adenylate cyclase, inhibited the purified cyclase by more than 80%. The extent of βγ-induced inhibition was not affected by the activation with Ca2+ and calmodulin. Moreover, the prior addition of the βγ-subunits to the cyclase did not prevent the subsequent activation of the enzyme by Ca2+ and calmodulin. We conclude that the βγ-subunits inhibit adenylate cyclase activity in a calmodulin-independent mode.

[学科分类] 药理学

[关键词] Adenylate cyclase;G protein βγ-subunit;Calmodulin