title: Interactions of adriamycin with a calcium binding site.
abstract: Terbium (Tb3+) luminescence has been used to investigate the interactions of adriamycin with a specific calcium binding protein, in the plasma membrane of GH3/B6 pituitary tumor cells. The luminescence intensity and lifetime of the Tb3+-GH3/B6 complex was quenched in the presence of adriamycin. According to Stern-Volmer analysis, the quenching of Tb3+-GH3/B6 luminescence was by both membrane bound adriamycin (Ka = 3.7 x 10(5) M-1) and free adriamycin (kq = 7.3 x 10(7) M-1 s-1). The data suggests that, the calcium binding site at the outer surface of the membrane is collisionally accessible to freely diffusing adriamycin; and, that the toxin receptor site is located near the bound metal ion.
authors.affiliation: Department of Physiology and Biophysics, Howard University College of Medicine, Washington, D.C. 20059.
authors.forename: R G
authors.initials: RG
authors.lastname: Canada
authors.forename: W
authors.initials: W
authors.lastname: Saway
authors.forename: E
authors.initials: E
authors.lastname: Thompson
mesh_terms: D000818:Animals; D002135:Calcium-Binding Proteins / Q000378:metabolism*; D002460:Cell Line; D002462:Cell Membrane / Q000378:metabolism; D004317:Doxorubicin / Q000378:metabolism*; D007700:Kinetics; D008163:Luminescent Measurements; D010911:Pituitary Neoplasms / Q000378:metabolism; D013725:Terbium
chemical_list: D002135:Calcium-Binding Proteins; D013725:Terbium; D004317:Doxorubicin