title: Structural requirements for the binding of benzodiazepines to their peripheral-type sites.
abstract: The DS19 Friend erythroleukemia cells possess peripheral-type benzodiazepine recognition sites that are similar to those characterized in other tissues and cells. These sites recognize only specific and well-defined ligand structures. In order for the benzodiazepines to bind to these sites, an alkyl group of 3 carbons or less is required at position 1, together with a carbonyl group at position 2. In addition, the binding affinity is enhanced by 4'-halogen or 4'-methoxy substituents, and by 7- or 2'-halogens. However, the affinity is decreased by substitutions at position 3 or 4. Central-type benzodiazepine binding in brain, on the other hand, is not affected by 1-alkyl groups and is inhibited by 4'-substitutions. Furthermore, unlike the peripheral-type site, the brain receptor is stereo-selective. These results demonstrate that the two binding sites are fundamentally different in their recognition of benzodiazepine ligands.
mesh_terms: D000818:Animals; D000927:Anticonvulsants / Q000378:metabolism; D001569:Benzodiazepines / Q000378:metabolism*; D001570:Benzodiazepinones / Q000378:metabolism; D001667:Binding, Competitive; D001921:Brain / Q000378:metabolism; D002460:Cell Line; D003975:Diazepam / Q000378:metabolism; D007942:Leukemia, Experimental / Q000378:metabolism; D051379:Mice; D051381:Rats; D011956:Receptors, Cell Surface / Q000378:metabolism*; D011963:Receptors, GABA-A; D013329:Structure-Activity Relationship
chemical_list: D000927:Anticonvulsants; D001570:Benzodiazepinones; D011956:Receptors, Cell Surface; D011963:Receptors, GABA-A; D001569:Benzodiazepines; C028513:4'-chlorodiazepam; D003975:Diazepam