title: Solubilization of human platelet vasopressin receptors.
abstract: The human platelet membrane receptor for vasopressin (AVP) has been solubilized with the cholic acid derivative detergent 3-( [3-cholamidopropyl)-dimethylammonio]-1-propane sulfonate. Rapid and simple separation of free tritiated AVP ( [3H]AVP) from the solubilized receptor-hormone complex was done by filtration through polyethylenimine-treated filters. [3H]AVP binds to this soluble receptor with an equilibrium dissociation constant of 11.03 +/- 1.86 nM and a maximal number of binding sites = 288 +/- 66 fmol/mg protein while the corresponding values of the membrane-bound receptor are 1.62 +/- 0.21 nM and 237 +/- 38 fmol/mg of protein, respectively. The Ki value for native AVP derived from competition experiments is 11.02 +/- 2.05 nM for the soluble receptor. Competition experiments with specific vascular and renal antagonists confirm that the solubilized receptor belongs to the V1-vascular subtype.
mesh_terms: D001127:Arginine Vasopressin / Q000378:metabolism; D001792:Blood Platelets / Q000032:analysis*; D002793:Cholic Acids / Q000494:pharmacology; D005374:Filtration; D006801:Humans; D011094:Polyethyleneimine / Q000494:pharmacology; D011945:Receptors, Angiotensin / Q000302:isolation & purification*; D017483:Receptors, Vasopressin; D012995:Solubility
chemical_list: D002793:Cholic Acids; D011945:Receptors, Angiotensin; D017483:Receptors, Vasopressin; D001127:Arginine Vasopressin; D011094:Polyethyleneimine; C028213:3-((3-cholamidopropyl)dimethylammonium)-1-propanesulfonate