FEBS Letters | |
Inhibition of catalytic unit of adenylate cyclase and activation of GTPase of Ni protein by βγ‐subunits of GTP‐binding proteins | |
Asakawa, Takeo1  Enomoto, Keiichi1  | |
[1] Department of Pharmacology, Saga Medical School, Saga 840-01, Japan | |
关键词: Adenylate cyclase Enzyme inhibition Niprotein GTPase ADP-ribosylation Islet-activating protein (Rat brain); | |
DOI : 10.1016/0014-5793(86)80650-0 | |
学科分类:生物化学/生物物理 | |
来源: John Wiley & Sons Ltd. | |
【 摘 要 】
A protein factor which inhibited adenylate cyclase was purified to apparent homogeneity from rat brain and identified as the βγ-subunits of the GTP-binding regulatory proteins of adenylate cyclase. (i) The βγ-subunits (protein factor) inhibited the partially purified catalytic unit of adenylate cyclase in the presence of an activator, forskolin or the stimulative regulatory protein (Ns), to 60 and 40% of the control, respectively; inhibition of the catalytic unit in the presence of forskolin required no guanine nucleotides. (ii) The subunits enhanced the GTPase activity of the purified α-subunit of the inhibitory regulatory protein (Niα) 3.8-fold, (iii) The subunits stimulated ADP-ribosylation of niα catalyzed by islet-activating protein (pertussis toxin). ADP-ribosylation had no effect on the GTPase activity of Niα in the presence of the βγ-subunits. The results suggest that direct inhibition of the catalytic unit by the βγ-subunits liberated from Ni is essential for the receptor-mediated inhibition of adenylate cyclase.
【 授权许可】
Unknown
【 预 览 】
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