Peptide subunits of gamma-aminobutyric acidA/benzodiazepine receptors from bovine cerebral cortex.
The gamma-aminobutyric acidA/benzodiazepine receptor complexes from bovine cerebral cortex were purified by immunoaffinity chromatography, and the main component peptide subunits were characterized. The peptide band originally thought to be a single beta subunit [57,000 Mr band in sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE)] is composed of at least four different peptides of 54,000-57,000 Mr. Two peptides of 55,000 and 57,000 Mr were recognized by the beta subunit-specific monoclonal antibody 62-3G1. Peptides in the range of 54,000-57,000 Mr were photoaffinity-labeled with [3H]muscimol. A different 57,000 Mr peptide was photoaffinity-labeled by [3H]flunitrazepam, but neither was recognized by the monoclonal antibody 62-3G1 nor photoaffinity-labeled with [3H]muscimol. Some peptides could be identified by their differential mobility shift in SDS-PAGE after treatment with endoglycosidase H. Two additional subunit peptides of 51,000 and 53,000 Mr were also photoaffinity-labeled by [3H]flunitrazepam and reacted with antiserum A. However, the 57,000 Mr peptide that also was photoaffinity-labeled by [3H]flunitrazepam did not react with antiserum A.
Park
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Department of Neurobiology and Behavior, State University of New York, Stony Brook.
de Blas
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D000345:Affinity Labels; D000818:Animals; D002417:Cattle; D002540:Cerebral Cortex / Q000378:metabolism*; D005445:Flunitrazepam / Q000378:metabolism; D006031:Glycosylation; D009118:Muscimol / Q000378:metabolism; D009479:Neuropeptides / Q000378:metabolism*; D010446:Peptide Fragments / Q000378:metabolism; D010449:Peptide Mapping; D011233:Precipitin Tests; D011963:Receptors, GABA-A / Q000378:metabolism*
D000345:Affinity Labels; D009479:Neuropeptides; D010446:Peptide Fragments; D011963:Receptors, GABA-A; D009118:Muscimol; D005445:Flunitrazepam