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Lateral diffusion, order parameter and phase transition in phospholipid bilayer membranes containing tocopheryl
Biochimica Et Biophysica Acta
|August 4, 1976
Summary
Tocopheryl acetate addition to dipalmitoyl phosphatidylcholine membranes decreases lateral diffusion and slightly increases order parameter. It also broadens the phase transition temperature range, indicating altered membrane fluidity.
Area of Science:
- Biochemistry
- Membrane Biophysics
- Physical Chemistry
Background:
- Lipid bilayers are fundamental to cell membranes.
- Tocopheryl acetate, a vitamin E derivative, is found in biological membranes.
- Understanding lipid-membrane interactions is crucial for cell function.
Purpose of the Study:
- To investigate the effects of tocopheryl acetate on dipalmitoyl phosphatidylcholine (DPPC) membrane properties.
- To determine how tocopheryl acetate influences membrane fluidity and phase behavior.
- To construct a phase diagram for DPPC/tocopheryl acetate mixtures.
Main Methods:
- Utilized pyrene excimer fluorescence for lateral diffusion measurements.
- Employed fatty acid spin labels for order parameter determination.
- Applied TEMPO spin labels to construct the phase diagram via partitioning studies.
Main Results:
- Tocopheryl acetate decreased the lateral diffusion coefficient of pyrene in DPPC membranes.
- A slight increase in the order parameter of fatty acid chains was observed in the inner membrane region.
- Tocopheryl acetate significantly broadened the phase transition temperature range of DPPC membranes.
- Complete miscibility of DPPC and tocopheryl acetate was noted in both solid and liquid crystalline states at low concentrations.
Conclusions:
- Tocopheryl acetate incorporation alters DPPC membrane dynamics and structural organization.
- The addition of tocopheryl acetate leads to a more ordered and less fluid membrane state.
- The phase behavior indicates significant miscibility and influences the lipid phase transition.