Buttriss J L, Diplock A T
Division of Biochemistry, United Medical School, London, U.K.
Biochim Biophys Acta. 1988 Sep 2;962(1):81-90. doi: 10.1016/0005-2760(88)90098-7.
(1) A method was devised for the subfractionation of normal rat liver and for the subfractionation of the mitochondrial fraction into inner and outer membrane fractions. The purity of the fractions was assessed using marker enzyme measurements. (2) alpha-Tocopherol was measured in all the fractions by a sensitive HPLC technique. Profiles of phospholipid fatty acids were also determined by gas-liquid chromatography in all the fractions, and these values were calculated in terms of the percentage of each fatty acid in the total fatty acid of the fraction, as well as of the mass of each fatty acid per mumol of phospholipid phosphorus. Tocopherol values were expressed as the mass of tocopherol per g wet liver and per mumol of phospholipid phosphorus. (3) The results show that the mitochondrial and microsomal fractions were the major tocopherol-containing fractions, and both the inner and outer mitochondrial fractions contained substantial amounts of alpha-tocopherol. (4) The mitochondrial and microsomal fractions also had the highest levels of polyunsaturated fatty acids (PUFA) in their phospholipid fraction, especially 20:4 and 22:6, which were particularly localised in the inner mitochondrial membrane fraction. The high inner mitochondrial and microsomal PUFA levels were particularly apparent when the sum of all the unsaturated fatty acids with three or more double bonds was calculated. (5) Calculation of molar ratios of of some phospholipid fatty acids to alpha-tocopherol gave values of the order of several thousand to one. (6) It is concluded that the protective effect of each molecule of alpha-tocopherol must be exerted towards a large number of molecules of membrane unsaturated fatty acids simultaneously. This perhaps implies specific localisation of tocopherol in regions of membrane particularly liable to attack, such as might be expected to occur close to respiratory enzymes that can donate electrons to molecular oxygen.
(1) 设计了一种方法，用于对正常大鼠肝脏进行亚分级分离，并将线粒体部分进一步分离为内膜和外膜部分。通过标记酶测定来评估各部分的纯度。(2) 采用灵敏的高效液相色谱技术测定所有部分中的α-生育酚。还通过气液色谱法测定了所有部分中磷脂脂肪酸的谱图，并根据各脂肪酸在该部分总脂肪酸中的百分比以及每微摩尔磷脂磷中各脂肪酸的质量来计算这些值。生育酚值以每克湿肝脏和每微摩尔磷脂磷中生育酚的质量表示。(3) 结果表明，线粒体和微粒体部分是含生育酚的主要部分，线粒体内膜和外膜部分均含有大量的α-生育酚。(4) 线粒体和微粒体部分的磷脂部分中多不饱和脂肪酸（PUFA）水平也最高，尤其是20:4和22:6，它们特别集中在线粒体内膜部分。当计算所有具有三个或更多双键的不饱和脂肪酸的总和时，线粒体内膜和微粒体中高含量的PUFA尤为明显。(5) 计算一些磷脂脂肪酸与α-生育酚的摩尔比得出的值约为几千比一。(6) 得出的结论是，每个α-生育酚分子的保护作用必须同时作用于大量的膜不饱和脂肪酸分子。这可能意味着生育酚在膜中特别容易受到攻击的区域有特定的定位，例如可能预期在靠近能将电子传递给分子氧的呼吸酶的地方发生。
