Gene/Protein
Disease
Symptom
Drug
Enzyme
Compound
Pivot Concepts:
Gene/Protein
Disease
Symptom
Drug
Enzyme
Compound
Target Concepts:
Gene/Protein
Disease
Symptom
Drug
Enzyme
Compound
Query: EC:4.6.1.1 (
adenylate cyclase
)
19,190
document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)
The regulation of
adenylate cyclase
by muscarinic cholinergic receptors has been studied in rat heart membranes. In the presence of isoproterenol the K0.5 for Mg2+-mediated activation of
adenylate cyclase
was 0.1 mM; the addition of the muscarinic receptor agonist oxotremorine increased the K0.5 for Mg2+, and activation by Mg2+ no longer followed mass action kinetics for a single site interaction. The extent of oxotremorine-mediated attenuation of
adenylate cyclase
exhibited a Mg2+ concentration dependence: in short-time assays at 0.25 mM free Mg2+ the attenuation of enzyme activity was 55 percent, whereas at 20mM Mg2+, only 20 percent inhibition was observed. The increase in the apparent K0.5 for Mg2+ in the presence of oxotremorine was less in 20 min assays than in 4 min assays. The effects of oxotremorine on the rates of activation and deactivation of
adenylate cyclase
also were examined.
Oxotremorine
increased the rate of deactivation of
adenylate cyclase
by two-fold. At low free Mg2+ concentrations, oxotremorine also decreased the rate of activation of
adenylate cyclase
in the presence of either 0.1 uM GTP gamma S or 1 uM GTP. An oxotremorine-mediated decrease in the rate of activation of
adenylate cyclase
activity was not detectable in the presence of greater than 3 mM Mg2+.
...
PMID:Muscarinic cholinergic receptor-mediated attenuation of adenylate cyclase activity in rat heart membranes. 399 32
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