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Predicate | Object |
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rdf:type | |
lifeskim:mentions | |
pubmed:issue |
5
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pubmed:dateCreated |
1981-6-23
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pubmed:abstractText |
The effects of alpha-tocopherol and related compounds on the membrane fluidity of liposomes composed of dipalmitoyl-lecithin or egg lecithin were studied by measuring the fluorescence polarization of DPH(1,6-diphenyl-1,3,5-hexatriene), a hydrophobic fluorescent probe distributed in the hydrocarbon region of lipid bilayers. The transition temperature of dipalmitoyl-lecithin liposomes was lowered on incorporation of alpha-tocopherol into the membranes. A similar effect was observed on incorporation of phytol or phytanic acid into liposomes, but not on incorporation of 2,2,5,7,8-pentamethyl-1-hydroxychroman as an alpha-tocopherol model compound (TMC) which lacks an isoprenoid side chain. Above the phase-transition temperatures, incorporation of alpha-tocopherol or TMC dose-dependently increased the polarization values of DPH in dipalmitoyl-lecithin and egg lecithin liposomes, while incorporation of phytol or phytanic acid had little effect or slightly lowered the polarization. These results suggest that the effect of alpha-tocopherol in lowering the phase-transition temperature depends on its hydrophobic side chain, and that its effect in decreasing the membrane fluidity above the phase-transition temperature depends on its hydrophylic chroman ring portion. Cholesterol had an effect similar to alpha-tocopherol on membrane fluidity. alpha-Tocopherol and cholesterol had independent effects in increasing the polarization of DPH above the phase-transition temperature when the two compounds were incorporated together into liposomes.
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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/Cholesterol,
http://linkedlifedata.com/resource/pubmed/chemical/Chromans,
http://linkedlifedata.com/resource/pubmed/chemical/Diphenylhexatriene,
http://linkedlifedata.com/resource/pubmed/chemical/Liposomes,
http://linkedlifedata.com/resource/pubmed/chemical/Pulmonary Surfactants,
http://linkedlifedata.com/resource/pubmed/chemical/Vitamin E
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pubmed:status |
MEDLINE
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pubmed:issn |
0301-4800
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pubmed:author | |
pubmed:issnType |
Print
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pubmed:volume |
26
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pubmed:owner |
NLM
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pubmed:authorsComplete |
Y
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pubmed:pagination |
427-34
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pubmed:dateRevised |
2000-12-18
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pubmed:meshHeading |
pubmed-meshheading:6894310-Cholesterol,
pubmed-meshheading:6894310-Chromans,
pubmed-meshheading:6894310-Diphenylhexatriene,
pubmed-meshheading:6894310-Dose-Response Relationship, Drug,
pubmed-meshheading:6894310-Fluorescence Polarization,
pubmed-meshheading:6894310-Liposomes,
pubmed-meshheading:6894310-Membrane Fluidity,
pubmed-meshheading:6894310-Pulmonary Surfactants,
pubmed-meshheading:6894310-Structure-Activity Relationship,
pubmed-meshheading:6894310-Temperature,
pubmed-meshheading:6894310-Vitamin E
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pubmed:year |
1980
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pubmed:articleTitle |
Fluorescence depolarization studies of phase transition and fluidity in lecithin liposomes containing alpha-tocopherol.
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pubmed:publicationType |
Journal Article
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