Kazan Institute of Biochemistry and Biophysics, FRC Kazan Scientific Center of RAS, P.O. Box 261, 420111 Kazan, Russia.
Int J Mol Sci. 2023 Aug 19;24(16):12977. doi: 10.3390/ijms241612977.
The GC-MS profiling of the endogenous oxylipins (Me/TMS) from cucumber ( L.) leaves, flowers, and fruit peels revealed a remarkable abundance of 16-hydroxy-9,12,14-octadecatrienoic acid (16-HOT). Incubations of homogenates from these organs with α-linolenic acid yielded 16()-hydroperoxide (16-HPOT) as a predominant product. Targeted proteomic analyses of these tissues revealed the presence of several highly homologous isoforms of the putative "9-lipoxygenase type 6". One of these isoenzymes (CsLOX3, an 877 amino acid polypeptide) was prepared by heterologous expression in and exhibited 16()- and 13()-lipoxygenase activity toward α-linolenic and linoleic acids, respectively. Furthermore, α-linolenate was a preferred substrate. The molecular structures of 16()-HOT and 16()-HPOT (Me or Me/TMS) were unequivocally confirmed by the mass spectral data, H-NMR, 2D H-H-COSY, TOCSY, HMBC, and HSQC spectra, as well as enantiomeric HPLC analyses. Thus, the vegetative CsLOX3, biosynthesizing 16()-HPOT, is the first 16()-LOX and ω3-LOX ever discovered. Eicosapentaenoic and hexadecatrienoic acids were also specifically transformed to the corresponding ω3()-hydroperoxides by CsLOX3.
黄瓜（L.）叶片、花朵和果皮内源氧代脂类（Me/TMS）的 GC-MS 分析显示，16-羟基-9,12,14-十八碳三烯酸（16-HOT）含量丰富。这些器官匀浆与α-亚麻酸孵育生成 16-（）-过氧化物（16-HPOT）作为主要产物。对这些组织的靶向蛋白质组学分析表明，存在几种假定的“9-脂氧合酶型 6”的高度同源同工酶。这些同工酶之一（CsLOX3，一种 877 个氨基酸的多肽）通过异源表达在 中制备，并对α-亚麻酸和亚油酸表现出 16-（）和 13-（）脂氧合酶活性，分别。此外，α-亚麻酸是首选的底物。16-（）-HOT 和 16-（）-HPOT（Me 或 Me/TMS）的分子结构通过质谱数据、H-NMR、2D H-H-COSY、TOCSY、HMBC 和 HSQC 谱以及对映体 HPLC 分析得到了明确证实。因此，合成 16-（）-HPOT 的植物性 CsLOX3 是第一个 16-LOX 和 ω3-LOX。二十碳五烯酸和十六碳三烯酸也被 CsLOX3 特异性转化为相应的 ω3-（）-过氧化物。
