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Transmembrane Distribution of Alpha-tocopherol in Single-lamellar Mixed Lipid Vesicles

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Journal J Membr Biol
Date 1981 Jan 30
PMID 7218332
Citations 3
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Abstract

A study of the molar ratio dependence of the incorporation of alpha-tocopherol into single-lamellar vesicles showed that the number of molecules which the bilayers can accommodate increased linearly with increasing alpha-tocopherol/phosphatidylcholine initial molar ratios till about 0.05, then approached a saturation limit. At 5 mol%, one alpha-tocopherol molecule per 60 phospholipids can be incorporated into the membranes. Up to this limit the distribution of alpha-tocopherol in the bilayers is uniform, while at initial molar ratios higher than 0.05 a disproportionation toward the inner monolayer of the vesicles is observed. The average outer/total ratio is found to be 0.27 +/- 0.03 at alpha-tocopherol/phosphatidylcholine molar ratios above 0.07 and is similar to asymmetrical distributions that have been reported in vesicles containing other one-chain amphiphiles (e.g., cholesterol). This large disproportionation is in contrast with the packing distribution of certain two-chain amphiphiles, and indicates that one of the driving forces for asymmetry formation in lipid bilayers might be dependent on the number of hydrocarbon chains per amphiphile molecule. A possible reason for the disproportionation effect observed in our experiments is the displacement of unsaturated phospholipids to the outer monolayer of the single-lamellar vesicles, by the more rigid isoprene units of alpha-tocopherol.

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References
1.
Fukuzawa K, Hayashi K, Suzuki A . Effects of alpha-tocopherol analogs on lysosome membranes and fatty acid monolayers. Chem Phys Lipids. 1977; 18(1):39-48. DOI: 10.1016/0009-3084(77)90025-1. View

2.
Fukuzawa K, Ikeno H, Tokumura A, Tsukatani H . Effect of alpha-tocopherol incorporation of glucose permeability and phase transition of lecithin liposomes. Chem Phys Lipids. 1979; 23(1):13-21. DOI: 10.1016/0009-3084(79)90019-7. View

3.
BARTLETT G . Phosphorus assay in column chromatography. J Biol Chem. 1959; 234(3):466-8. View

4.
LUCY J . Functional and structural aspects of biological membranes: a suggested structural role for vitamin E in the control of membrane permeability and stability. Ann N Y Acad Sci. 1972; 203:4-11. DOI: 10.1111/j.1749-6632.1972.tb27849.x. View

5.
DIPLOCK A, LUCY J . The biochemical modes of action of vitamin e and selenium: A hypothesis. FEBS Lett. 1973; 29(3):205-210. DOI: 10.1016/0014-5793(73)80020-1. View