Metabolic control and regulation of the tricarboxylic acid cycle in photosynthetic and heterotrophic plant tissues
Metabolic control and regulation of the tricarboxylic acid cycle in photosynthetic and heterotrophic plant tissues
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DOI：
10.1111/j.1365-3040.2011.02332.x
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发表时间：
2012-01-01
影响因子：
7.3
通讯作者：
Fernie, Alisdair R.
中科院分区：
文献类型：
--
作者：
Araujo, Wagner L.;Nunes-Nesi, Adriano;Fernie, Alisdair R.
三羧酸（TCA）循环是光合和异养植物器官呼吸代谢的重要组成部分。最近，番茄TCA循环的所有主要基因都已被克隆，从而可以产生一系列转基因植物，其中途径中的大多数酶都逐渐减少。对这些植物的调查提供了一个几乎完整的视图，在这一重要途径的控制分布。柠檬酸合成酶、顺乌头酸酶、异柠檬酸脱氢酶、琥珀酰CoA连接酶、琥珀酸脱氢酶、琥珀酸脱氢酶和苹果酸脱氢酶对呼吸的控制系数分别为-0.4，0.964，-0.123，0.0008，0.289，0.601和1.76;而2-酮戊二酸脱氢酶在马铃薯块茎中的控制系数估计为0.786。因此，这些结果表明，该途径的控制分布在苹果酸脱氢酶，乌头酸酶，琥珀酸脱氢酶，琥珀酸脱氢酶和2-酮戊二酸脱氢酶。不寻常的分布控制估计在这里是一致的特定的非循环通量模式和胞质旁路，在照明叶操作。这些意见进行了讨论的背景下，已知的酶的调节特性和一些说明性的例子，该途径如何响应环境变化。
The tricarboxylic acid (TCA) cycle is a crucial component of respiratory metabolism in both photosynthetic and heterotrophic plant organs. All of the major genes of the tomato TCA cycle have been cloned recently, allowing the generation of a suite of transgenic plants in which the majority of the enzymes in the pathway are progressively decreased. Investigations of these plants have provided an almost complete view of the distribution of control in this important pathway. Our studies suggest that citrate synthase, aconitase, isocitrate dehydrogenase, succinyl CoA ligase, succinate dehydrogenase, fumarase and malate dehydrogenase have control coefficients flux for respiration of -0.4, 0.964, -0.123, 0.0008, 0.289, 0.601 and 1.76, respectively; while 2-oxoglutarate dehydrogenase is estimated to have a control coefficient of 0.786 in potato tubers. These results thus indicate that the control of this pathway is distributed among malate dehydrogenase, aconitase, fumarase, succinate dehydrogenase and 2-oxoglutarate dehydrogenase. The unusual distribution of control estimated here is consistent with specific non-cyclic flux mode and cytosolic bypasses that operate in illuminated leaves. These observations are discussed in the context of known regulatory properties of the enzymes and some illustrative examples of how the pathway responds to environmental change are given.