Heparin was found to be the most potent inhibitor of rat ovarian luteinizing hormone-sensitive adenylate cyclase (I50 = 2 microgram/ml) when compared to other naturally occurring glycosamin oglycans. This inhibition was also apparent when this enzyme was stimulated by follicle-stimulating hormone or prostaglandin E2. Heparin was also found to inhibit glucagon-sensitive rat hepatic adenylate cyc...

Carbachol, an activator of muscarinic acetylcholine receptors of NG108-15 hybrid cells, inhibits adenylate cyclase [ATP pyrophosphate-lyase (cyclizing), EC 4.6.1.1] rapidly and reversibly and slowly evokes a 200-300% increase in adenylate cyclase activity over a period of 24-30 hr. Both the inhibition of adenylate cyclase and the gradual increase in enzyme activity are dependent on muscarinic a...

Tetraploid strains of Saccharomyces cerevisiae carrying different dosages of the CYR1+ gene have been constructed. Adenylate cyclase activity observed in these tetraploid strains was proportional to the dosage of the active CYR1+ gene. Of the 57 mutants requiring adenosine 3',5'-monophosphate for growth at 35 degrees C, two allelic temperature-sensitive cyr1 mutants produced thermolabile adenyl...

Various serine proteases (e.g., trypsin, alpha-chymotrypsin, Pronase, and subtilisin) stimulate adenylate cyclase [ATP pyrophosphate-lyase (cyclizing), EC 4.6.1.1] activity in a membrane-enriched fraction of the rat ovary. Maximum stimulation is observed at protease concentrations ranging from 3 to 10 mug/ml. Higher protease concentrations inhibit ovarian adenylate cyclase in a dose-dependent m...

5'-Guanylylimidodiphosphate (Gpp(NH)-p) stimulates adenylate cyclase [ATP-pyrophosphate-lyase (cyclizing), EC 4.6.1.1] activity in plasma membranes isolated from frog and salmon erythrocytes, from rat adrenal, hepatic, and fat cells, and from bovine thyroid cells. The nucleotide acts cooperatively with the various hormones (glucagon, secretin, ACTH, thyrotropin, and catecholamines) that stimula...

The calmodulin and calcium dependence of human adenylate cyclase from the second part of the duodenum was assessed in washed particulate preparations of biopsy specimens by investigating (a) the concentration dependent effects of free [Ca2+] on enzyme activity, (b) the effects of exogenous calmodulin on enzyme activity in ethylene glycol bis (b-aminoethyl ether)N,N'-tetra-acetic acid (EGTA) was...

Cell membranes from clones of cultured S49 mouse lymphoma cells were incubated with [*2511iodohydroxybenzyipindolol, a specific, high affinity ligand for the /3-adrenergic receptor, and guanyl-5’-yl imidodiphosphate, which activates adenylate cyclase irreversibly. Membranes were then solubilized with 0.1% Lubrol PX, and hydrodynamic properties of the ligand receptor complex and of adenylate cyc...

The longitudinal and transverse distributions of the synapse-specific phosphoprotein Protein I and adenylate cyclase in the rat spinal cord were studied. Protein I was found to be enriched in all cervical and midlumbar (L3-L5) segments, and sparse in midthoracic and sacral segments. Adenylate cyclase activity was high in all cervical and lumbosacral segments, and low in mid-thoracic segments. C...

The effect of adenosine in insulin secretion and adenylate cyclase activity of rat islets of Langerhans was investigated. Adenosine inhibited insulin secretion stimulated by glucose, glucagon, prostaglandin E2, tolbutamine and theophylline. Adenosine decreased basal adenylate cyclase activity of the islets as well as that stimulated by glucagon prostaglandin E2 and GTP, although fluoride-stimul...

Sugars such as glucose are transported into Escherichia coli by a coupled phosphorylation mechanism (the phosphoenolpyruvate:sugar phosphotransferase system, PTS). Transport of sugars through the PTS results in inhibition of adenylate cyclase [ATP pyrophosphate-lyase (cyclizing), EC 4.6.1.1] activity by a mechanism involving a change in the state of phosphorylation of PTS proteins. Other sugars...