Envelope membranes from spinach chloroplasts are a site of metabolism of fatty acid hydroperoxides
Envelope membranes from spinach chloroplasts are a site of metabolism of fatty acid hydroperoxides
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DOI：
10.1104/pp.110.2.445
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发表时间：
1996-02-01
期刊：
影响因子：
7.4
通讯作者：
Joyard, J
中科院分区：
文献类型：
--
作者：
Blee, E;Joyard, J
研究发现，菠菜叶绿体包膜中的酶能催化脂肪酸氢过氧化物的快速分解。相比之下，在基质或类囊体中没有检测到这种活性。在包膜制备中，9s -氢过氧-10(E)、12(Z)-十八烯二酸、13s -氢过氧-9(Z)、11(E) -十八烯二酸或13s -氢过氧-9(Z)、11(E)、15(Z)-十八烯三酸的转化速率几乎相同(1-2 μ mol min（-1) mg（-1）蛋白）。形成的产物通过反相高压液相色谱分离，并进一步通过气相色谱-质谱分析进行表征。脂肪酸氢过氧化物被(a)分解成醛和氧酸片段，对应于氢过氧化物裂解酶的功能，(b)分解成由氢过氧化物脱水酶合成的氧化烯自发形成的酮，(c)分解成由尚未被表征的系统酶合成的羟基化合物，(d)分解成由脂氧合酶的氢过氧化物酶活性产生的氧烯。因此，叶绿体包膜含有一整套催化多种脂肪酸衍生物合成的酶，其中一些酶可能作为调控分子。结果表明，质体包膜在植物细胞中具有新的作用。
Enzymes in envelope membranes from spinach (Spinacia oleracea L.) chloroplasts were found to catalyze the rapid breakdown of fatty acid hydroperoxides. In contrast, no such activities were detected in the stroma or in thylakoids. In preparations of envelope membranes, 9S-hydroperox-10(E),12(Z)-octadecadienoic acid, 13S-hydroperoxy-9(Z),11 (E)-octadecadienoic acid, or 13S-hydroperoxy-9(Z),11(E), 15(Z)-octadecatrienoic acid were transformed at almost the same rates (1-2 mu mol min(-1) mg(-1) protein). The products formed were separated by reversed-phase high-pressure liquid chromatography and further characterized by gas chromatography-mass spectrometry. Fatty acid hydroperoxides were cleaved (a) into aldehydes and oxoacid fragments, corresponding to the functioning of a hydroperoxide lyase, (b) into ketols that were spontaneously formed from allene oxide synthesized by a hydroperoxide dehydratase, (c) into hydroxy compounds synthesized enzymatically by a system that has not yet been characterized, and (d) into oxoenes resulting from the hydroperoxidase activity of a lipoxygenase. Chloroplast envelope membranes therefore contain a whole set of enzymes that catalyze the synthesis of a variety of fatty acid derivatives, some of which may act as regulatory molecules. The results presented demonstrate a new role for the plastid envelope within the plant cell.