Delta 12-oleate desaturase-related enzymes associated with formation of conjugated trans-delta 11, cis-delta 13 double bonds.
Delta 12-oleate desaturase-related enzymes associated with formation of conjugated trans-delta 11, cis-delta 13 double bonds.
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Delta 12-油酸去饱和酶相关酶与缀合的反式 Delta 11、顺式 Delta 13 双键的形成相关。
DOI：
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发表时间：
2003
期刊：
影响因子：
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通讯作者：
J. Imamura
中科院分区：
文献类型：
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作者：
M. Iwabuchi;J. Kohno;J. Imamura
共轭亚麻酸作为主要种子油存在于几种植物中。石榴酸（或异辛酸）是在C（18）碳链中含有顺式-δ 9、反式-δ 11、顺式-δ 13双键的共轭亚麻酸异构体。在这里，我们报告的cDNA，TkFac和PgFac，分离自天花粉和石榴，编码一类共轭相关的形成trans-delta 11，cis-delta 13双键。在种子特异性napin启动子的转录控制下，拟南芥种子中TkFac和PgFac的表达导致石榴酸的积累高达总种子油的约10%（w/w）。与此相反，没有石榴酸被发现在脂质叶片，即使当共轭驱动下的花椰菜花叶病毒35 S启动子的控制。在培养基中无外源脂肪酸生长的酵母细胞中，TkFac和PgFac表达导致石榴酸积累，伴随着16：2delta（9 cis，12 cis）和18：2delta（9 cis，12 cis）的产生。因此，TkFac和PgFac被定义为具有缀合酶和δ 12-油酸去饱和酶活性的双功能酶。此外，我们还证明了16：2delta（9 cis，12 cis）和18：3delta（9 cis，12 cis，15 cis）以及18：2delta（9 cis，12 cis）是形成trans-delta 11和cis-delta 13双键的潜在底物。
Conjugated linolenic acids are present as major seed oils in several plant species. Punicic acid (or trichosanic acid) is a conjugated linolenic acid isomer containing cis-delta9, trans-delta11, cis-delta13 double bonds in the C(18) carbon chain. Here we report cDNAs, TkFac and PgFac, isolated from Trichosanthes kirilowii and Punica granatum, that encode a class of conjugases associated with the formation of trans-delta11, cis-delta13 double bonds. Expression of TkFac and PgFac in Arabidopsis seeds under transcriptional control of the seed-specific napin promoter resulted in accumulation of punicic acid up to approximately 10% (w/w) of the total seed oils. In contrast, no punicic acid was found in lipids from leaves even when the conjugases were driven under control of the cauliflower mosaic virus 35S promoter. In yeast cells grown without exogenous fatty acids in the culture medium, TkFac and PgFac expression resulted in punicic acid accumulation accompanied by 16:2delta(9cis, 12cis) and 18:2delta(9cis, 12cis) production. Thus, TkFac and PgFac are defined as bifunctional enzymes having both conjugase and delta12-oleate desaturase activity. Furthermore, we demonstrate that 16:2delta(9cis, 12cis) and 18:3delta(9cis, 12cis, 15cis) as well as 18:2delta(9cis, 12cis) are potential substrates for the conjugases to form trans-delta11 and cis-delta13 double bonds.