ANTIOXIDANT ACTION OF UBIQUINOL HOMOLOGS WITH DIFFERENT ISOPRENOID CHAIN-LENGTH IN BIOMEMBRANES

被引：136

作者：

KAGAN, VE

SERBINOVA, EA

KOYNOVA, GM

KITANOVA, SA

TYURIN, VA

STOYTCHEV, TS

QUINN, PJ

PACKER, L

机构：

[1] Institute of Physiology, Bulgarian Academy of Sciences, Sofia

[2] Institute of Evolutionary Biochemistry, Acad. Sci. USSR, Leningrad

[3] Department of Biochemistry, King's College London, London, W8 7AH, Campden Hill Road

[4] Department of Molecular and Cell Biology, University of California, Berkeley

来源：

FREE RADICAL BIOLOGY AND MEDICINE | 1990年 / 9卷 / 02期

关键词：

Antioxidant action; Chemiluminescence; Cytochrome P-450; Free radicals; Tocopherol regeneration; Ubiquinone; Vitamin E;

D O I：

10.1016/0891-5849(90)90114-X

中图分类号：

Q5 [生物化学]; Q7 [分子生物学];

学科分类号：

071010 ; 081704 ;

摘要：

Ubiquinones (CoQn) are intrinsic lipid components of many membranes. Besides their role in electron-transfer reactions they may act as free radical scavengers, yet their antioxidant function has received relatively little study. The efficiency of ubiquinols of varying isoprenoid chain length (from Q0 to Q10) in preventing (Fe2+ + ascorbate)-dependent or (Fe2+ + NADPH)-dependent lipid peroxidation was investigated in rat liver microsomes and brain synaptosomes and mitochondria. Ubiquinols, the reduced forms of CoQn, possess much greater antioxidant activity than the oxidized ubiquinone forms. In homogenous solution the radical scavenging activity of ubiquinol homologues does not depend on the length of their isoprenoid chain. However in membranes ubiquinols with short isoprenoid chains (Q1-Q4) are much more potent inhibitors of lipid peroxidation than the longer chain homologues (Q5-Q10). It is found that: i) the inhibitory action, that is, antioxidant efficiency of short-chain ubiquinols decreases in order Q1 > Q2 > Q3 > Q4; ii) the antioxidant efficiency of long-chain ubiquinols is only slightly dependent on their concentrations in the order Q5 > Q6 > Q7 > Q8 > Q9 > Q10 and iii) the antioxidant efficiency of Q0 is markedly less than that of other homologues. Interaction of ubiquinols with oxygen radicals was followed by their effects on luminol-activated chemiluminescence. Ubiquinols Q1-Q4 at 0.1 mM completely inhibit the luminol-activated NADPH-dependent chemiluminescent response of microsomes, while homologues Q6-Q10 exert no effect. In contrast to ubiquinol Q10 (ubiquinone Q10) ubiquinone Q1 synergistically enhances NADPH-dependent regeneration of endogenous vitamin E in microsomes thus providing for higher antioxidant protection against lipid peroxidation. The differences in the antioxidant potency of ubiquinols in membranes are suggested to result from differences in partitioning into membranes, intramembrane mobility and non-uniform distribution of ubiquinols resulting in differing efficiency of interaction with oxygen and lipid radicals as well as different efficiency of ubiquinols in regeneration of endogenous vitamin E. © 1990.

引用

页码：117 / 126

页数：10

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