Second messenger cyclic adenosine monophosphate

The second messenger, cyclic adenosine monophosphate (cAMP), is thought to mediate the bronchodila-tor effects of the adrenomimetics. Adrenomimetics enhance the production of cAMP by activating adenylyl cyclase, the enzyme that converts adenosine triphosphate (ATP) to cAMP. This process is triggered by the interaction of the adrenomimetics with 2-(tdrenoceptors on airway smooth muscle. 

Glucagon exerts its ejfects on cells by binding to a receptor on the cell surface, which stimulates the synthesis of the intracellular second messenger, cyclic adenosine monophosphate (cAMP) (Fig. 26.3). cAMP activates protein kinase A, which phosphorylates key regulatory enzymes, activating some and inhibiting others. Changes of cAMP levels also induce or repress the synthesis of a number of enzymes. Insulin promotes the dephosphorylation of these key enzymes. 

Adenyl cyclase The enzyme (also known as adenylate, or adenylyl cyclase) that catalyses the formation of the second messenger cyclic adenosine-.l A -monophosphate (cAMP) from ATP following the activation of a Gs protein-coupled receptor. 

Cyclic AMP Stimulation or inhibition of the biosynthesis of the second messenger cyclic adenosine-S jS -monophosphate occurs through the activation of Gs or G protein-coupled neurotransmitter receptors, respectively. 

The most common second messenger activated by protein/peptide hormones and catecholamines is cyclic adenosine monophosphate (cAMP). The pathway by which cAMP is formed and alters cellular function is illustrated in Figure 10.1. The process begins when the hormone binds to its receptor. These receptors are quite large and span the plasma membrane. On the cytoplasmic surface of the membrane, the receptor is associated with a G protein that serves as the transducer molecule. In other words, the G protein acts as an intermediary between the receptor and the second messengers that will alter cellular activity. These proteins are referred to as G proteins because they bind with guanosine nucleotides. In an unstimulated cell, the inactive G protein binds guanosine diphosphate (GDP). When the hormone... 

TTie second messenger, for example cyclic adenosine monophosphate (cAMP), then activates cAMP-dependent protein kinase which modulates the function of a broad range of membrane receptors, intracellular enzymes, ion channels and transcription factors. 

Compounds 28 and 29 are pentacoordinated models of the activated state of 3, 5 -cyclic adenosine monophosphate (cAMP), which plays a dominant role as second messenger in cell metabolism regulation69. A conformational transmission effect found by dynamic H and 13C NMR70 results in 51% of trans position for the Oa) and 0(2) atoms, but only when... 

Glucagon appears to exert its effects on liver cells by a classic adenyl cyclase-cyclic adenosine monophosphate (cAMP) second messenger system (see Chapter 4).93 Glucagon binds to a specific receptor located on the hepatic cell membrane. This stimulates the activity of the adenyl cyclase enzyme that transforms adeno-... 

Cyclic adenosine monophosphate (ABBR cAMP) The ring-shaped conformation of adenosine monophosphate, which is important in acting as a second messenger in mediating the intracellular response to drug stimulation. 

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