Membrane stabilizing effect of vitamin E: existence of a hydrogen bond between alpha-tocopherol and phospholipids in bilayer liposomes.
In order to elucidate the existence of a hydrogen bond between alpha-tocopherol and phospholipids in bilayer liposomes, the effects of the presence or absence of alpha-tocopherol or its acetate on either the permeability of liposomes to chromate ions or the fluidity of liposomes composed of the different kinds of lecithin [egg yolk phosphatidylcholine (EPC), 1-oleoyl-2-palmitoylphosphatidylcholine (OPPC), or 1-O-oleyl-2-O-palmitoylphosphatidylcholine (OPPCE)] were examined. From the results obtained, it was concluded that the hydroxyl group of alpha-tocopherol is hydrogen bonded to the carbonyl group of a fatty acid ester in the phospholipids of bilayer liposomes in order to retain alpha-tocopherol molecule in the space close to the surface of membranes formed by the unsaturated fatty acid moiety of phospholipids.
Urano
S
S
Tokyo Metropolitan Institute of Gerontology, Japan.
Kitahara
M
M
Kato
Y
Y
Hasegawa
Y
Y
Matsuo
M
M
D002840:Chromates / Q000378:metabolism; D006860:Hydrogen Bonding; D008051:Lipid Bilayers / Q000378:metabolism*; D008081:Liposomes / Q000378:metabolism*; D008560:Membrane Fluidity / Q000187:drug effects; D008563:Membrane Lipids / Q000737:chemistry* / Q000378:metabolism; D010743:Phospholipids / Q000378:metabolism*; D013329:Structure-Activity Relationship; D014810:Vitamin E / Q000494:pharmacology*
D002840:Chromates; D008051:Lipid Bilayers; D008081:Liposomes; D008563:Membrane Lipids; D010743:Phospholipids; D014810:Vitamin E