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rdf:type | |
lifeskim:mentions | |
pubmed:issue |
1-2
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pubmed:dateCreated |
1993-2-19
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pubmed:abstractText |
Studies were made on the position and dynamics of the OH-group of alpha-tocopherol in phospholipid membranes. There was no difference in the spin-lattice (T1) relaxation times at the 5a-position of alpha-tocopherol labeled with 13C- or C19F3-determined from the nuclear magnetic resonance (NMR) spectra of liposomes positively charged with stearylamine (SA) and negatively charged with dicetylphosphate (DCP). The zeta-potentials of egg yolk phosphatidylcholine (EYPC) liposomes with and without SA or DCP were not affected by incorporation of 20 mol% alpha-tocopherol, though incorporation of 10 mol% ascorbyl-palmitate decreased the zeta-potentials of EYPC and EYPC-SA liposomes. The P==O stretching band (1235 cm-1) of the phosphate group and C==O stretching band (1734 cm-1) of the acyl ester linkage in dimyristoylphosphatidylcholine (DMPC) liposomes, measured by Fourier transform-infrared (FT-IR) spectroscopy, were not changed by incorporation of alpha-tocopherol. These results suggest that no specific interaction occurred between the OH-group of alpha-tocopherol and the polar interfacial region of the bilayer. The dynamic quenching effects of n-(N-oxy-4,4'-dimethyloxazolidine-2-yl)stearic acids (n-NSs) on the intrinsic fluorescence of alpha-tocopherol were in the order 5-NS > 7-NS = 12-NS > 16-NS. Acrylamide, a water-soluble fluorescence quencher with a very low capacity to penetrate through phospholipid bilayers, had very low quenching efficiency. These results indicate that the bulk of the chromanol moiety of alpha-tocopherol is located in a position close to that occupied by the nitroxide group of 5-NS in the membranes and is poorly exposed at the membrane surface.(ABSTRACT TRUNCATED AT 250 WORDS)
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pubmed:language |
eng
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pubmed:journal | |
pubmed:citationSubset |
IM
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pubmed:chemical |
http://linkedlifedata.com/resource/pubmed/chemical/Free Radical Scavengers,
http://linkedlifedata.com/resource/pubmed/chemical/Liposomes,
http://linkedlifedata.com/resource/pubmed/chemical/Membranes, Artificial,
http://linkedlifedata.com/resource/pubmed/chemical/Phospholipids,
http://linkedlifedata.com/resource/pubmed/chemical/Spin Labels,
http://linkedlifedata.com/resource/pubmed/chemical/Vitamin E
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pubmed:status |
MEDLINE
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pubmed:month |
Nov
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pubmed:issn |
0009-3084
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pubmed:author | |
pubmed:issnType |
Print
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pubmed:volume |
63
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pubmed:owner |
NLM
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pubmed:authorsComplete |
Y
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pubmed:pagination |
69-75
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pubmed:dateRevised |
2006-4-17
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pubmed:meshHeading |
pubmed-meshheading:1336717-Electrochemistry,
pubmed-meshheading:1336717-Electron Spin Resonance Spectroscopy,
pubmed-meshheading:1336717-Free Radical Scavengers,
pubmed-meshheading:1336717-Liposomes,
pubmed-meshheading:1336717-Magnetic Resonance Spectroscopy,
pubmed-meshheading:1336717-Membrane Potentials,
pubmed-meshheading:1336717-Membranes, Artificial,
pubmed-meshheading:1336717-Oxidation-Reduction,
pubmed-meshheading:1336717-Phospholipids,
pubmed-meshheading:1336717-Spin Labels,
pubmed-meshheading:1336717-Vitamin E
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pubmed:year |
1992
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pubmed:articleTitle |
Location and dynamics of alpha-tocopherol in model phospholipid membranes with different charges.
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pubmed:affiliation |
Faculty of Pharmaceutical Sciences, Tokushima University, Japan.
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pubmed:publicationType |
Journal Article
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