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m ‐Sulfonate Benzene Diazonium Chloride: A Powerful Affinity Label for the γ‐Aminobutyric Acid Binding Site from Rat Brain
Author(s) -
Bouchet MarieJeanne,
Jacques Patrice,
Ilien Brigitte,
Goeldner Maurice,
Hirth Christian
Publication year - 1992
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.1471-4159.1992.tb08454.x
Subject(s) - muscimol , chemistry , dissociation constant , binding site , membrane , sulfonate , chloride , ligand (biochemistry) , dissociation (chemistry) , ligand binding assay , benzene , chromatography , gabaa receptor , biochemistry , organic chemistry , receptor , sodium
m ‐Sulfonate benzene diazonium chloride (MSBD) was used to affinity‐label the γ‐aminobutyric acid (GABA) binding site from rat brain membranes. To assess the irreversibility of the labeling reaction, we used an efficient ligand dissociation procedure combined to a rapid [ 3 H]muscimol binding assay, both steps being performed on filter‐adsorbed membranes. Inactivation of specific [ 3 H]‐muscimol binding sites by MSBD and its prevention by GABA were both time‐ and concentration‐dependent. The time course of MSBD labeling was shortened as the pH of the incubation medium was increased from 6.2 to 8. These data suggest that MSBD can efficiently label the GABA binding site through alkylation of a residue having an apparent dissociation constant around neutrality.