title: Azidobutyryl clentiazem, a new photoactivatable diltiazem analog, labels benzothiazepine binding sites in the alpha 1 subunit of the skeletal muscle calcium channel.
abstract: [3H]Azidobutyryl clentiazem, a new photoactivable diltiazem derivative, has a higher binding affinity than azidobutyryl diltiazem. It can be covalently incorporated into the alpha 1 subunit of the skeletal muscle calcium channel by UV irradiation, which allows the benzothiazepine binding site to be determined. The photolabeled alpha 1 subunit and its proteolytic fragments were analyzed with a panel of sequence-directed antibodies. The results suggest that the linker region between segment S5 and S6 of domain IV is involved in benzothiazepine binding. This site is different from the dihydropyridine and verapamil binding sites.
authors.affiliation: Faculty of Pharmaceutical Sciences, Hokkaido University, Sapporo, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Watanabe
authors.forename: H
authors.initials: H
authors.lastname: Kalasz
authors.forename: H
authors.initials: H
authors.lastname: Yabana
authors.forename: A
authors.initials: A
authors.lastname: Kuniyasu
authors.forename: J
authors.initials: J
authors.lastname: Mershon
authors.forename: K
authors.initials: K
authors.lastname: Itagaki
authors.forename: P L
authors.initials: PL
authors.lastname: Vaghy
authors.forename: K
authors.initials: K
authors.lastname: Naito
authors.forename: H
authors.initials: H
authors.lastname: Nakayama
authors.forename: A
authors.initials: A
authors.lastname: Schwartz
mesh_terms: D000345:Affinity Labels / Q000378:metabolism*; D000818:Animals; D001386:Azides / Q000378:metabolism*; D001569:Benzodiazepines / Q000378:metabolism*; D001665:Binding Sites; D001667:Binding, Competitive; D002121:Calcium Channel Blockers / Q000378:metabolism*; D015220:Calcium Channels / Q000378:metabolism*; D002417:Cattle; D004110:Diltiazem / Q000031:analogs & derivatives* / Q000378:metabolism; D009132:Muscles / Q000378:metabolism*; D011233:Precipitin Tests; D011817:Rabbits; D014700:Verapamil / Q000378:metabolism
chemical_list: D000345:Affinity Labels; D001386:Azides; D002121:Calcium Channel Blockers; D015220:Calcium Channels; C062012:3-(4-azidobutyryloxy)diltiazem; D001569:Benzodiazepines; D014700:Verapamil; D004110:Diltiazem