gamma-Aminobutyric acid/benzodiazepine receptor protein carries binding sites for both ligands on both two major peptide subunits |
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Authors: | M Bureau R W Olsen |
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Affiliation: | Department of Pharmacology, School of Medicine, University of California, Los Angeles 90024. |
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Abstract: | Affinity column-purified GABA-benzodiazepine receptor proteins from human, cow, and rat brain were photoaffinity labeled with both [3H]flunitrazepam and [3H]muscimol and examined by gel electrophoresis in sodium dodecyl sulfate. Using high receptor protein concentrations (1 microM), the benzodiazepine ligand [3H]flunitrazepam was incorporated covalently primarily into the expected 52 kiloDalton major subunit but also significantly into a second 57 kiloDalton peptide. Likewise the GABA ligand [3H]muscimol photolabeled primarily the 57 kiloDalton peptide but also to some extent the 52 kiloDalton peptide. This cross-labeling suggests strongly that both major subunits carry binding sites for both GABA and benzodiazepine. |
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