Solubilization and reconstitution of α2‐adrenergic receptors from rat and calf brain

Roxana KREMENETZKY*, Daphne ATLAS

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

13 Scopus citations

Abstract

Sodium cholate and digitonin were used to solubilize α2‐adrenergic receptors from rat and calf brain. Sodium cholate extracted 40–50% of the membrane protein and 25–30% of the binding capacity. Digitonin extracted only 20–30% of the membrane protein and only 10–15% of the binding capacity of the native membranes. Both detergents were removed by dialysis in the presence of phospholipids, and the solubilized protein was precipitated upon addition of poly(ethyleneglycol) and magnesium. In the solubilization/reconstitution process no purification of the α2‐adrenergic receptor was obtained, most probably due to its inactivation by the solubilization conditions. The reconstituted protein(s) tested for binding properties, using p‐[3H]aminoclonidine and/or [3H]clonidine, maintained the pharmacological profile of the native α2‐adrenergic receptor. The potency order of various α2‐agonists and α2‐antagonists as well as their stereoselectivity were identical to those of the native α2‐receptor. Specific receptor binding decreases in the presence of the guanyl nucleotides GTP or guanosine 5′‐[β, γ‐imido]‐triphosphate but not ATP, thus indicating a co‐solubilization of GTP regulatory components (stimulatory protein Ns or inhibitory protein Ni or both). Adenylate cyclase activity of the reconstituted preparation is stimulated threefold by sodium fluoride, suggesting the presence of both Ns‐protein and the catalytic unit (C) in the reconstituted protein(s).

Original languageEnglish
Pages (from-to)573-577
Number of pages5
JournalEuropean Journal of Biochemistry
Volume138
Issue number3
DOIs
StatePublished - Feb 1984

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