Kühn H, Heydeck D, Sprecher H
Institute of Biochemistry, School of Medicine (Charité), Humboldt University, Berlin, F.R.G.
Biochim Biophys Acta. 1991 Jan 28;1081(2):129-34. doi: 10.1016/0005-2760(91)90017-c.
A set of octadecadienoic acid isomers and selected eicosatrienoic acids were tested as substrates for the lipoxygenases from soybeans and reticulocytes. Among the dienoic fatty acids, 8Z,11Z-octadecadienoic acid containing a n - 9 doubly allylic methylene group turned out to be the best substrate for the reticulocyte enzyme. This substrate was converted to its corresponding n - 7 hydroperoxy derivative. The soybean lipoxygenase, in contrast, prefers the 9Z,12Z-octadecadienoic acid (linoleic acid) which is oxygenated to its n - 6 hydroperoxy derivative. In both cases a strong preference for the LS-isomer has been observed. Analysis of the oxygenation products formed from various eicosatrienoic acids indicated that 8Z,11Z,14Z-eicosatrienoic acid was converted by the reticulocyte enzyme to its 12S- and 15S-hydroperoxy derivative in a ratio of about 1:7 (dual positional specificity), whereas the 7Z,10Z,13Z-isomer was oxygenated predominantly (greater than 97%) to its 14S-hydroperoxy derivative (singular positional specificity). 9Z,12Z,15Z-eicosatrienoic acid was oxygenated with a dual positional specificity to the corresponding 13- and 16-hydroperoxy compounds in a ratio of about 7:1. The soybean lipoxygenase converts the 8Z,11Z,14Z-isomer with a singular positional specificity to the corresponding 15S-hydroperoxy derivatives. The 9Z,12Z,15Z-eicosatrienoic acid, however, was oxygenated with a dual positional specificity to its 13S-hydroperoxy and 16S-hydroperoxy derivative in a ratio of about 1:4.
一组十八碳二烯酸异构体和选定的二十碳三烯酸被作为大豆和网织红细胞脂氧合酶的底物进行测试。在二烯脂肪酸中，含有一个n - 9双烯丙基亚甲基的8Z,11Z - 十八碳二烯酸被证明是网织红细胞酶的最佳底物。该底物被转化为其相应的n - 7氢过氧化物衍生物。相比之下，大豆脂氧合酶更喜欢9Z,12Z - 十八碳二烯酸（亚油酸），它被氧化为其n - 6氢过氧化物衍生物。在这两种情况下，都观察到对LS - 异构体有强烈的偏好。对由各种二十碳三烯酸形成的氧化产物的分析表明，8Z,11Z,14Z - 二十碳三烯酸被网织红细胞酶以约1:7的比例转化为其12S - 和15S - 氢过氧化物衍生物（双重位置特异性），而7Z,10Z,13Z - 异构体主要（大于97%）被氧化为其14S - 氢过氧化物衍生物（单一位置特异性）。9Z,12Z,15Z - 二十碳三烯酸以双重位置特异性被氧化为相应的13 - 和16 - 氢过氧化物化合物，比例约为7:1。大豆脂氧合酶以单一位置特异性将8Z,11Z,14Z - 异构体转化为相应的15S - 氢过氧化物衍生物。然而，9Z,12Z,15Z - 二十碳三烯酸以双重位置特异性被氧化为其13S - 氢过氧化物和16S - 氢过氧化物衍生物，比例约为1:4。
