Copper ions and diamide induce a high affinity guanine-nucleotide-insensitive state for muscarinic agonists

David Gurwitz*, Bruce Baron, Mordechai Sokolovsky

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

Abstract

The binding capacity of [3H]-acetylcholine for muscarinic receptors of rat cerebral cortex membranes is increased in the presence of Cu2+ ions from 690 to 1320 fmol/mg protein with no significant change in affinity. Membranes treated with 50 μM Cu2+ and washed retain the increased binding capacity. Agonist binding in copper-treated membranes is insensitive to guanylylimidodiphosphate even at high concentrations (>200 μM). Similar results were obtained when the sulfhydryl oxidizing agent, diamide (2 mM) was substituted for Cu2+ in the treatment of membranes. These data suggest the involvement of inter- or intramolecular SH S-S transitions in the interaction between the muscarinic receptor and a guanine nucleotide binding regulatory protein.

Original languageEnglish
Pages (from-to)271-277
Number of pages7
JournalBiochemical and Biophysical Research Communications
Volume120
Issue number1
DOIs
StatePublished - 16 Apr 1984

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