Isolation and purification of benzodiazepine receptor and its endogenous ligand
Neuropharmacologypart B: 881-883
The subunit structure of benzodiazepine (BDZP) receptor can be analyzed by SDS-PAGE following the distribution of its covalently linked ligand, 3H-flunitrazepam (FNZP). Two subunits with a molecular weight of 50,000 ± 5,000 and 12,000 ± 2,000 dalton, respectively, are obtained. The 50,000-dalton subunit has been purified extensively by preparative SDS-PAGE. An endogenous substance which competes with FNZP for the binding to BDZP receptor has been isolated and purified to homogeneity by ultrafiltration, gel filtration and repetitive HPLC separation. The purified substance has the following properties: (1) heat stable, (2) a major absorption peak at 220 nm and a minor peak at 313 nm, (3) insensitive to DNAase and RNAase, (4) protease, causes a slight decrease in the activity, and (5) it contains about 5–10% of amino acid moiety.