title: Phase Equilibria in binary mixtures of dimyristoylphosphatidylcholine and cardiolipin.
abstract: Paramagnetic resonance spectra of the spin-label 2,2,6,6-tetramethylpiperidinyl-l-oxy have been used to study phase separations in binary mixtures of dimyristoyl-phosphatidylcholine and cardiolipin. Two different samples of cardiolipin were used: (i) One sample contained calcium ions at a mole ratio of calcium:cardiolipin = 1:2; the experimental data support the view that cardiolipin is present in the bilayer membrane as calcium ion linked dimers, (CL)2 Ca2+. (ii) A calcium-free sodium cardiolipin sample yielded remarkable spin-label partition data that were quite different from those obtained in the presence of Ca2+. In both cases the spin-label data provide evidence for compound formation and for fluid-fluid immiscibility in the bilayer membrane.
mesh_terms: D002118:Calcium; D002308:Cardiolipins; D003497:Cyclic N-Oxides; D004134:Dimyristoylphosphatidylcholine; D004578:Electron Spin Resonance Spectroscopy; D007700:Kinetics; D008081:Liposomes; D008433:Mathematics; D010713:Phosphatidylcholines; D013050:Spectrometry, Fluorescence; D013113:Spin Labels
chemical_list: D002308:Cardiolipins; D003497:Cyclic N-Oxides; D008081:Liposomes; D010713:Phosphatidylcholines; D013113:Spin Labels; D002118:Calcium; C001803:tempol; D004134:Dimyristoylphosphatidylcholine