title: Mechanism of action of "ruthenium red" compounds on Ca2+ ionophore from sarcoplasmic reticulum (Ca2+ + Mg2+)- adenosine triphosphatase and lipid bilayer.
abstract: Sarcoplasmic reticulum (Ca2+ + Mg2+)-ATPase was previously shown to have Ca2+-dependent and -selective ionophoric activity when tested in oxidized cholesterol lipid bilayer membranes (Shamoo, A. E., and MacLennan, D. H. (1974) Proc. Natl. Acad. Sci. U. S. A. 71, 3522). ruthenium red, a known inhibitor of (Ca2+ + Mg2+)-ATPase, is found to inhibit the Ca2+-ionophoric activity associated with (Ca2+ + Mg2+)-ATPase. Furthermore, ruthenium red alone acts as an anion-selective ionophore in lipid bilayers with the the following selectivity sequence for anions: l- greater than Cl-, Br- greater than F- greater than NO3-. The PCl-/PNa+ ratio was approximately 4/l. The presence of ruthenium red in excess of Ca2+ ionophore in lipid bilayer experiments converts the cation selectivity of the bilayer due to Ca2+ ionophore into anion selectivity.
mesh_terms: D000251:Adenosine Triphosphatases / Q000378:metabolism*; D000818:Animals; D000838:Anions; D002118:Calcium / Q000494:pharmacology*; D002784:Cholesterol; D004553:Electric Conductivity; D004789:Enzyme Activation / Q000187:drug effects; D007476:Ionophores / Q000378:metabolism*; D008274:Magnesium / Q000494:pharmacology; D008567:Membranes, Artificial; D008954:Models, Biological; D011817:Rabbits; D012428:Ruthenium / Q000494:pharmacology*; D012430:Ruthenium Red / Q000494:pharmacology*; D012519:Sarcoplasmic Reticulum / Q000201:enzymology*
chemical_list: D000838:Anions; D007476:Ionophores; D008567:Membranes, Artificial; D012430:Ruthenium Red; D012428:Ruthenium; D002784:Cholesterol; D000251:Adenosine Triphosphatases; D008274:Magnesium; D002118:Calcium