Action of vitamin E as antioxidant in phospholipid liposomal membranes as studied by spin label technique.
Action of vitamin E as antioxidant in phospholipid liposomal membranes as studied by spin label technique.
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通过自旋标记技术研究维生素 E 在磷脂脂质体膜中作为抗氧化剂的作用。
DOI：
10.3177/jnsv.34.25
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发表时间：
1988
影响因子：
1.6
通讯作者：
S. Urano
中科院分区：
文献类型：
--
作者：
M. Takahashi;J. Tsuchiya;E. Niki;S. Urano
用自旋标记技术研究了维生素E在磷脂酰胆碱脂质体膜中的作用。随着饱和磷脂酰胆碱、胆固醇和α-生育酚浓度的增加，脂质体膜的流动性降低。然而，α-生育酚在其生理浓度下的物理效应相当小。研究了不同结构的色原烷醇对膜流动性的影响。脂质体膜的流动性随着6-色原烷醇2位侧链长度的增加而降低。当2-位侧链不具有支链甲基时，这种影响较小。生育酚对膜流动性的影响在膜的内部较大。抗坏血酸驻留在水相相互作用的氮氧自由基自旋探针纳入膜和速率较小的氮氧自由基被埋在磷脂双层更深。掺入脂质体膜中的自旋探针随着氧化的进行而消耗。α-生育酚抑制膜的氧化和自旋探针的减少，但是当α-生育酚耗尽时，自旋探针减少，并且随着氧化的进行，膜变得更加刚性。
The action of alpha-tocopherol in the phosphatidylcholine liposomal membranes was studied by spin label technique in order to elucidate the role of vitamin E in the membranes. The fluidity of the liposomal membranes decreased with increasing concentrations of saturated phosphatidylcholine, cholesterol, and alpha-tocopherol. However, the physical effect of alpha-tocopherol was quite small at its physiological concentrations. The effects of structure of various kinds of chromanols on the membrane fluidity were studied. The fluidity of the liposomal membranes decreased with increasing length of the side chain at 2-position of 6-chromanols. This effect was smaller when the side chain at the 2-position did not possess branched methyl group. The effect of tocopherols on the membrane fluidity was larger in the inner part of the membranes. Ascorbic acid residing in the aqueous phase interacted with the nitroxide spin probe incorporated into the membranes and the rate was smaller as the nitroxide group was buried deeper in the phospholipid bilayer. The spin probes incorporated into liposomal membranes were consumed as the oxidation proceeded. alpha-Tocopherol suppressed both the oxidation of membranes and the decrease of spin probe, but when alpha-tocopherol was depleted, the spin probe decreased and the membranes became more rigid as the oxidation proceeded.