Partitioning and localization of spin-labeled amantadine in lipid bilayers: an EPR study.
EPR was used to study the distribution of the spin-labeled amantadine (AA-SL) between the bulk hydrophobic-hydrocarbon solvent, light paraffin oil, and water and between hydrophobic-hydrocarbon chain region of lipid membranes and water. The AA-SL molecules were soluble in both hydrophobic and polar regions of investigated systems. It was shown that the partition coefficient of AA-SL between the hydrocarbon region of the L-alpha-dimyristoylphosphatidylcholine fluid-phase membrane and water is much higher than between bulk hydrocarbon solvent and water. Furthermore, the partitioning of AA-SL into membranes of multilamellar liposomes made of L-alpha-dimyristoylphosphatidylcholine, L-alpha-dipalmitoylphosphatidylcholine, and L-alpha-distearoylphosphatidylcholine was studied as a function of temperature, indicating no abrupt change at the main phase transition of these membranes. It is also clear from our data that AA-SL can penetrate into the gel-phase membrane practically with the same partitioning as into the fluid-phase membrane. Furthermore, it was shown that at least part of the AA-SL molecule is deeply buried in the hydrocarbon chain region of the membrane.
Biophysics Department, Institute of Molecular Biology, Jagiellonian University, Krakow, Poland.
W K
WK
Subczynski
J
J
Wojas
V
V
Pezeshk
A
A
Pezeshk
D000547:Amantadine / Q000032:analysis*; D000998:Antiviral Agents / Q000032:analysis*; D004578:Electron Spin Resonance Spectroscopy; D008051:Lipid Bilayers / Q000737:chemistry*; D008081:Liposomes; D013113:Spin Labels; D014867:Water
D000998:Antiviral Agents; D008051:Lipid Bilayers; D008081:Liposomes; D013113:Spin Labels; D014867:Water; D000547:Amantadine