Rapid-cell membrane-embedded enzymes

Rapid-Cell Membrane-Embedded Enzymes A medication particle binds to the surface of the cell, causing an enzyme inside the cell to initiate a physiological response. 

Adrenoceptors are proteins embedded in the cell membrane that are coupled through a G-protein to effector mechanisms that translate conformational changes caused by activation of the receptor into a biochemical event within the cell. All of the )3-adrenoceptors are coupled through specific G-proteins (Gg) to the activation of adenylyl cyclase (45). When the receptor is stimulated by an agonist, adenylyl cyclase is activated to catalyze conversion of ATP to cyclic-adenosine monophosphate (cAMP), which diffuses through the cell for at least short distances to modulate biochemical events remote from the synaptic cleft. Modu-lationof biochemical events by cAMP includes a phosphorylation cascade of other proteins. cAMP is rapidly deactivated by hydrolysis of the phosphodiester bond by the enzyme phosphodiesterase. The a,-receptor may use more than one effector system, depending on the location of the receptor however, to date the best understood effector system of the a,-receptor appears to be similar to that of the )3-re-... 

---