1999 Fiscal Year Final Research Report Summary
EFFECTS OF ACTIVE HYDROGEN IN DIFFERENT REACTION SITES ON OXIDATION OF POLYUNSATURATED LIPIDS
| Project/Area Number |
09660225
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Fisheries chemistry
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| Research Institution | Tokyo University of Fisheries |
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Principal Investigator |
OHSHIMA Toshiaki Tokyo University of Fisheries, Dept. of Fisheries, Associate Professor, 水産学部, 助教授 (70134856)
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| Co-Investigator(Kenkyū-buntansha) |
大島 敏明 東京水産大学, 水産学部, 助教授 (70134856)
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| Project Period (FY) |
1997 – 1999
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| Keywords | phosphtidylcholine / oxidation / hydroperoxide / positional isomer / cholesterol / tocopherol / arachidonic acid / liposomes |
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| Research Abstract |
The oxidation of 1-Hexadecanoyl-2-[cis, cis, cis, cis-5,8,11,14-eicosatetraenoyl]-sn-glycero-3-phosphocholine (PC16:0-20:4) was initiated by AAPH or AMVN in a homogeneous solution of methanol or in liposomes with existence of cholesterol or alpha-tocopherol to investigate the effect of changing the environments of reaction site. The hydroperoxide positional isomers generated from oxidized arachidonyl group of the PC were converted to TMS derivatives after reduction of hydroperoxy group as well as hydrogenation of double bonds. The TMS derivatives thus obtained were analysed by mass spectrometry.
The ratio of two hydroperoxide isomers, 5-hydroperoxy arachidonic acid (5-OOH) and 15-hydroperoxy arachidonic acid, was around 1 in the oxidation of the PC in methanol. The original ratio, 5-OOH/15-OOH, obtained in the oxidation in liposomes increased to around two by addition of alpha-tocopherol with a molar ration to PC being 0.02. In more small concentration of alpha-tocopherol in the liposomes, there was no effect on the formation of hydroperoxide isomers.
These results suggested that alpha-tocopherol which coexists with PC in a liposomes bi-layer functioned as a hydrogen donor to PC and reduce the imbalance of certain hydroperoxide isomers which occurs in the liposomes system.
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