Branched-Chain Amino Acid Metabolism in Arabidopsis thaliana.
Branched-Chain Amino Acid Metabolism in Arabidopsis thaliana.
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DOI：
10.1199/tab.0137
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发表时间：
2010-01-01
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影响因子：
--
通讯作者：
Binder, Stefan
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作者：
Binder, Stefan
缬氨酸、亮氨酸和异亮氨酸构成了支链氨基酸（BCAAs）的一小群，根据它们的小支链烃残基进行分类。与动物不同，植物能够从丙酮酸、2-氧丁酸和乙酰辅酶a中重新合成这些氨基酸。在植物中，生物合成遵循微生物中为形成这些氨基酸而建立的典型反应途径。Val和Ile是用一组酶在两个平行的途径合成的。从Val生物合成的最终中间体到Leu分支的途径。这种氨基酸的形成需要三步途径产生由亚甲基拉长的2-氧酸。在拟南芥和其他芸苔科植物中，同源的三步通路也参与了Met链延伸的生物合成所需的脂肪族硫代葡萄糖苷，这是芸苔科植物中一类重要的特化代谢物。这是初级代谢和特化代谢途径进化关系的一个主要例子。与动物类似，植物也有降解支链氨基酸的能力。长期以来，人们一直不清楚支链氨基酸转换的重要性，但现在看来，在某些环境条件下，分解过程可能是相关的。本文综述了拟南芥BCAA代谢、调控及其特点等方面的研究进展。
Valine, leucine and isoleucine form the small group of branched-chain amino acids (BCAAs) classified by their small branched hydrocarbon residues. Unlike animals, plants are able to de novo synthesize these amino acids from pyruvate, 2-oxobutanoate and acetyl-CoA. In plants, biosynthesis follows the typical reaction pathways established for the formation of these amino acids in microorganisms. Val and Ile are synthesized in two parallel pathways using a single set of enzymes. The pathway to Leu branches of from the final intermediate of Val biosynthesis. The formation of this amino acid requires a three-step pathway generating a 2-oxoacid elongated by a methylene group. In Arabidopsis thaliana and other Brassicaceae, a homologous three-step pathway is also involved in Met chain elongation required for the biosynthesis of aliphatic glucosinolates, an important class of specialized metabolites in Brassicaceae. This is a prime example for the evolutionary relationship of pathways from primary and specialized metabolism. Similar to animals, plants also have the ability to degrade BCAAs. The importance of BCAA turnover has long been unclear, but now it seems apparent that the breakdown process might by relevant under certain environmental conditions. In this review, I summarize the current knowledge about BCAA metabolism, its regulation and its particular features in Arabidopsis thaliana.