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Solubilization of Active Brain α 1‐ Adrenoceptors by a Zwitterionic Detergent
Author(s) -
Guicheney Pascale,
Rappaport Alain,
Marcel Dominique
Publication year - 1983
Publication title -
journal of neurochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.75
H-Index - 229
eISSN - 1471-4159
pISSN - 0022-3042
DOI - 10.1111/j.1471-4159.1983.tb11813.x
Subject(s) - chaps , prazosin , chemistry , membrane , receptor , chromatography , polyethylene glycol , centrifugation , ligand (biochemistry) , binding site , biochemistry , antagonist
Solubilization of rat brain α 1 ‐adrenoceptors was performed by treatment with 6 m M CHAPS (3–[(3‐cholamidopropyl)dimethylammonio] ‐ 1 ‐ propanesulfon‐ate). The α 1 ‐adrenoceptor antagonist [ 3 H]prazosin was shown to bind reversibly and specifically to the soluble extract obtained after centrifugation at 150,000 ± g for 1 h. Separation of the soluble [ 3 H]prazosin‐bound complexes was performed by the polyethylene glycol precipitation technique followed by filtration. A Scatchard plot of the concentration‐dependent binding curve showed only one class of binding sites, with a high affinity for [ 3 H]prazosin. Affinity of the solubilized receptors for the ligand increased as the CHAPS concentration in the assay medium decreased; the number of binding sites remained unchanged (=70 fmol/mg protein). This corresponds to a 30% recovery of original membrane sites. The solubilized receptors presented the same characteristics of specificity and stereospecificity as membrane α 1 ‐adrenoceptors. Moreover, 150 m M NaCl was found to modulate the affinity of epinephrine for the [ 3 H]prazosin‐bound soluble complex, as previously described for membrane preparations. Thus, CHAPS appears to be a suitable detergent for solubilizing rat brain α 1 ‐adrenoceptors and preserving their functional activities.