title: Blocking of catecholamine activation of adenylate cyclase by N, N'dicyclohexyl carbodiimide in turkey erythrocytes.
abstract: Incubation of erythrocytes or their isolated membranes with N, N'dicyclohexyl carbodiimide (DCC) blocked isoproterenol activation of the adenylate cyclase. Fluoride activation remained unaffected. L-epinephrine and DL-propranolol partially and transiently protected the system against DCC. D-Epinephrine and dopamine did not protect. The enzyme system preactivated by isoproterenol plus Gpp(NH)p was no longer sensitive to DCC. In contrast to the water insoluble DCC, a water soluble carbodiimide acted only at high concentration and blocked fluoride as well as catecholamine activation of the adenylate cyclase. The findings indicate that DCC attacks a group on, or near, the beta-adrenergic receptor and that this group is located in a hydrophobic region of the cell membrane. It is argued that a low nominal concentration of DCC in the aqueous suspension of erythrocytes actually represents a very high concentration of DCC in the hydrophobic region of the cell membranes, near the beta-adrenergic receptor. The reaction with DCC may prove to be a useful tool in future analyses of beta-adrenergic receptor function.
mesh_terms: D000262:Adenylyl Cyclases / Q000097:blood*; D000818:Animals; D002234:Carbodiimides / Q000494:pharmacology*; D002395:Catecholamines / Q000494:pharmacology*; D004024:Dicyclohexylcarbodiimide / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D004789:Enzyme Activation / Q000187:drug effects; D004910:Erythrocyte Membrane / Q000187:drug effects / Q000201:enzymology; D005459:Fluorides / Q000494:pharmacology; D006150:Guanine Nucleotides / Q000494:pharmacology; D007545:Isoproterenol / Q000494:pharmacology; D011943:Receptors, Adrenergic, beta / Q000187:drug effects; D012995:Solubility; D014422:Turkeys
chemical_list: D002234:Carbodiimides; D002395:Catecholamines; D006150:Guanine Nucleotides; D011943:Receptors, Adrenergic, beta; D004024:Dicyclohexylcarbodiimide; D000262:Adenylyl Cyclases; D007545:Isoproterenol; D005459:Fluorides