Topic
Cyclase
About: Cyclase is a research topic. Over the lifetime, 10162 publications have been published within this topic receiving 388566 citations.
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01 Jan 1979
TL;DR: Serotonin activation of adenylate cyclase [ATP pyrophosphate-lyase (cyclizing), EC 4.6.1.1] of NCB-20 neuroblastoma cells with an activation constant of 530 nM, but has little or no effect on cellular cyclic AMP or cyclic GMP content of NIE-115 or NG108-15 hybrid cells as discussed by the authors.
Abstract: Serotonin activates adenylate cyclase [ATP pyrophosphate-lyase (cyclizing), EC 4.6.1.1] of NCB-20 neuroblastoma--brain hybrid cells with an activation constant of 530 nM, but has little or no effect on cellular cyclic AMP or cyclic GMP content of NIE-115 neuroblastoma or NG108-15 hybrid cells. In homogenates of NCB-20 hybrid cells, lysergic acid diethylamide stimulates adenylate cyclase activity (Kact = 12 nM) and partially inhibits (Ki = 10 nM) the stimulation of adenylate cyclase activity by serotonin. No desensitization was detected of serotonin receptors coupled to adenylate cyclase. Serotonin also depolarizes NCB-20, NG108-15, and NIE-115 cells and increases acetylcholine release. Serotonin receptors mediating depolarizing responses desensitize rapidly and reversibly, and the depolarizing effects of serotonin are neither mimicked nor inhibited by lysergic acid diethylamide. These results indicate that (i) NCB-20 cells possess at least two species of serotonin receptors, which independently regulate cellular functions, (ii) activation of adenylate cyclase does not directly affect membrane potential or acetylcholine release, and (iii) serotonin-dependent cell depolarization does not affect cyclic AMP or cyclic GMP synthesis in the cell lines tested.
104 citations
Journal Article•
TL;DR: Data are presented that Li, too, markedly reduces activity of beta-adrenergic adenylate cyclase in humans, and the effect is specific, since the plasma cyclic AMP response to glucagon is not inhibited.
104 citations
TL;DR: It was concluded that adenyl cyclase seems not to be a normal constituent of brush borders, like NaK-ATPase, who are present in plasma membrane preparations derived largely from the basal and lateral margins of the epithelial cells, both may be phospholipid dependent enzymes and both are affected by cholera toxin.
Abstract: Brush borders and plasma membranes have been purified from mucosal epithelial cells of rabbit ileum under control conditions and after treatment for 3 hr with cholera toxin in vivo. The activity of several enzymes in these preparations was measured. It was concluded that adenyl cyclase, like NaK-ATPase, seems not to be a normal constituent of brush borders. Both these enzymes are present in plasma membrane preparations derived largely from the basal and lateral margins of the epithelial cells, both may be phospholipid dependent enzymes and both are affected by cholera toxin. Adenyl cyclase activity is increased while NaK-ATPase is decreased. The activities of alkaline phosphatase, leucineaminopeptidase, 5′-nucleotidase, glucose-6-phosphatase, and Mg-ATPase were not found to be affected by the toxin. Cholera toxin, which makes contact with the luminal side of the epithelial cells, in the natural disease and in the experimental model, would appear to exert its pathologic effect on adenyl cyclase at the opposite (basal and lateral) side of the cells.
104 citations
104 citations
TL;DR: Selective inhibition of the glucagon-inactivating components of liver cell membranes allows more meaningful kinetic characterization of the hormone-receptor interaction in these membranes and may also aid in further studies designed to isolate and purify the receptors.
103 citations