EFFECT OF POLAR CAROTENOIDS ON THE OXYGEN DIFFUSION-CONCENTRATION PRODUCT IN LIPID BILAYERS - AN EPR SPIN LABEL STUDY
EFFECT OF POLAR CAROTENOIDS ON THE OXYGEN DIFFUSION-CONCENTRATION PRODUCT IN LIPID BILAYERS - AN EPR SPIN LABEL STUDY
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DOI：
10.1016/0005-2736(91)90061-c
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发表时间：
1991-09-10
期刊：
影响因子：
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通讯作者：
SIELEWIESIUK, J
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文献类型：
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作者：
SUBCZYNSKI, WK;MARKOWSKA, E;SIELEWIESIUK, J
氧扩散浓度的产品，确定在磷脂酰胆碱（PC）双层氧加宽的自旋标记EPR谱。 脂肪酸自旋标记的使用使得可以用相同的样品进行结构和血氧测量。 我们发现，极性类胡萝卜素，玉米黄质和紫黄质，增加订购的烃链饱和（二肉豆蔻酰-PC）和不饱和（蛋黄PC）膜，也显着降低这些膜的烃区域中的氧扩散浓度产品。 在25 ℃下，在10摩尔%的类胡萝卜素的存在下，产物比纯PC膜小约30%。 类胡萝卜素的插入降低了双层中心部分的氧扩散-浓缩产物，而对极性头基区域的产物影响不大。 相反，胆固醇分子显著减少膜表面上和附近的产物，并且在双层中间不改变其（饱和PC）或增加其（不饱和PC）（Subczynski，W.K.，海德，J.S.和Kusumi，A.等人（1989）Proc. Acad. Sci. USA 86，4474-4478）。 氧扩散-浓度乘积的降低可能是类胡萝卜素保护活性的一种机制，这在植物和动物细胞中在光照和黑暗中同样有效。
The oxygen diffusion-concentration product was determined in phosphatidylcholine (PC) bilayers from oxygen broadening of the spin label EPR spectra. The use of fatty acid spin labels makes it possible to do structural and oximetric measurements with the same sample. We find that polar carotenoids, zeaxanthin and violaxanthin, increase ordering of hydrocarbon chains in saturated (dimyristoyl-PC) and unsaturated (egg yolk PC) membranes and also significantly decrease the oxygen diffusion-concentration product in the hydrocarbon region of these membranes. At 25-degrees-C in the presence of 10 mol% of carotenoids, the product is about 30% smaller than in pure PC membranes. Intercalation of carotenoids decreases the oxygen diffusion-concentration product in the central part of the bilayer and has little effect on the product in the polar head group region. In contrast, cholesterol molecules significantly reduce the product on and near the membrane surface, and do not change it (saturated PC) or increase it (unsaturated PC) in the middle of the bilayer (Subczynski, W.K., Hyde, J.S. and Kusumi, A. (1989) Proc. Natl. Acad. Sci. USA 86, 4474-4478). The decrease of oxygen diffusion-concentration product may be a mechanism of carotenoid protective activity, which should be effective in plant and animal cells in the light as well as in the dark.