Dual effect of N-ethylmaleimide on agonist binding to bovine heart muscarinic receptors.
M2-Muscarinic acetylcholine receptors are identified in membrane preparations from calf heart by binding of [3H]quinuclidinyl benzilate. The alkylating reagent N-ethylmaleimide provokes two major changes in the competition binding characteristics of the agonist carbachol. At low temperature (0 degrees C), the reagent provokes a rightward shift and steepening of the competition curve in a GTP-like manner. This can be attributed to alkylation of the adenylate cyclase-regulating component Gi. At 30 degrees C, the reagent also increases the affinity of the agonist for the receptor, presumably by direct alkylation of the receptor.
Vauquelin
G
G
Department of Protein Chemistry, Free University Brussels, Sint-Genesius Rode, Belgium.
Vanderheyden
P
P
Ebinger
G
G
D000262:Adenylyl Cyclases / Q000378:metabolism; D000818:Animals; D001667:Binding, Competitive / Q000187:drug effects; D002217:Carbachol / Q000378:metabolism; D002417:Cattle; D005033:Ethylmaleimide / Q000494:pharmacology*; D006160:Guanosine Triphosphate / Q000494:pharmacology; D006321:Heart / Q000187:drug effects; D066298:In Vitro Techniques; D009206:Myocardium / Q000378:metabolism*; D010277:Parasympathomimetics / Q000378:metabolism*; D011813:Quinuclidinyl Benzilate; D011976:Receptors, Muscarinic / Q000187:drug effects / Q000378:metabolism*
D010277:Parasympathomimetics; D011976:Receptors, Muscarinic; D011813:Quinuclidinyl Benzilate; D006160:Guanosine Triphosphate; D002217:Carbachol; D000262:Adenylyl Cyclases; D005033:Ethylmaleimide