Kazan Institute of Biochemistry and Biophysics, Kazan Research Center, Russian Academy of Sciences, Russia.
Biochemistry (Mosc). 2010 Jun;75(6):708-16. doi: 10.1134/s0006297910060052.
7,10,13-Hexadecatrienoic acid (16:3) is abundant in many plant species. However, its metabolism through the lipoxygenase pathway is not sufficiently understood. The goal of present work was to investigate the oxygenation of 16:3 by different plant lipoxygenases and to study the occurrence of oxygenated derivatives of 16:3 in plant seedlings. The recombinant maize 9-lipoxygenase specifically converted 16:3 into (7S)-hydroperoxide. Identification of this novel oxylipin was substantiated by data of GC-MS, LC-MS/MS, 1H-NMR, and 2D-COSY as well as by deuterium labeling from [(2)H(6)]16:3. Soybean lipoxygenase 1 produced 91% (11S)-hydroperoxide and 6% racemic 14-hydroperoxide. Recombinant soybean lipoxygenase 2 (specifically oxidizing linoleate into 13-hydroperoxide) lacked any specificity towards 16:3. Lipoxygenase 2 produced 7-, 8-, 10-, 11-, 13-, and 14-hydroperoxides of 16:3, as well as a significant amount of bis-allylic 9-hydroperoxide. Seedlings of several examined plant species possessed free hydroxy derivatives of 16:3 (HHTs), as well as their ethyl esters. Interestingly, HHTs occur not only in "16:3 plants", but also in typical "18:3 plants" like pea and soybean seedlings.
7,10,13-十六碳三烯酸（16:3）在许多植物物种中含量丰富。然而，其通过脂氧合酶途径的代谢尚未得到充分理解。目前的工作目标是研究不同植物脂氧合酶对 16:3 的氧化作用，并研究 16:3 的氧化衍生物在植物幼苗中的存在情况。重组玉米 9-脂氧合酶特异性地将 16:3 转化为（7S）-氢过氧化物。这种新型氧化脂素的鉴定得到了 GC-MS、LC-MS/MS、1H-NMR 和 2D-COSY 以及 [(2)H(6)]16:3 的氘标记数据的证实。大豆脂氧合酶 1 产生 91%（11S）-氢过氧化物和 6%的外消旋 14-氢过氧化物。重组大豆脂氧合酶 2（特异性氧化亚油酸生成 13-氢过氧化物）对 16:3 没有任何特异性。脂氧合酶 2 产生了 16:3 的 7-、8-、10-、11-、13-和 14-氢过氧化物，以及相当数量的双烯丙基 9-氢过氧化物。几种被检测植物的幼苗都含有 16:3 的游离羟基衍生物（HHTs）及其乙酯。有趣的是，HHTs 不仅存在于“16:3 植物”中，也存在于典型的“18:3 植物”如豌豆和大豆幼苗中。
