Solubilization and characterization of endothelin-1 receptors in rat cardiac tissue.
Adult rat cardiac endothelin-1 (ET-1) receptors were solubilized with 0.5% digitonin and then characterized. The receptors retained binding activity after solubilization. Binding was saturable (KD of 0.065 +/- 0.004 nM, Bmax of 94.6 +/- 4.5 fmol/mg protein; Hill coefficient of 0.987 +/- 0.017 n = 6) and pH dependent, with the binding increasing as the pH was decreased from 10 to 4, but decreasing dramatically as pH dropped to 2. Specifically bound [125I]-ET-1 was not dissociated by 2 x 10(-7) M unlabelled ET-1, but was dissociated by pH 10 and 2. Returning the pH to 7.4 restored the binding activity of the receptors. Unlabelled ET-1 (10(-12) - 10(-7) M) and sarafotoxin S6b(10(-12) - 10(-7) M) competed with [125I]-ET-1 for binding to the receptors.
Liu
J J
JJ
Department of Medicine, University of Melbourne, Austin Hospital, Heidelberg, Victoria, Australia.
Kelly
J
J
Casley
D J
DJ
Johnston
C I
CI
Nayler
W G
WG
D000818:Animals; D001667:Binding, Competitive; D002462:Cell Membrane / Q000378:metabolism; D004072:Digitonin; D016232:Endothelins; D004730:Endothelium, Vascular; D005260:Female; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D009206:Myocardium / Q000378:metabolism*; D010455:Peptides / Q000378:metabolism; D051381:Rats; D011919:Rats, Inbred Strains; D011956:Receptors, Cell Surface / Q000302:isolation & purification* / Q000378:metabolism; D017466:Receptors, Endothelin
D016232:Endothelins; D010455:Peptides; D011956:Receptors, Cell Surface; D017466:Receptors, Endothelin; D004072:Digitonin