Flavonoid biosynthesis in the tea plant Camellia sinensis:: properties of enzymes of the prominent epicatechin and catechin pathways
Flavonoid biosynthesis in the tea plant Camellia sinensis:: properties of enzymes of the prominent epicatechin and catechin pathways
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DOI：
10.1016/j.abb.2004.08.003
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发表时间：
2004-11-01
影响因子：
3.9
通讯作者：
Fischer, TC
中科院分区：
文献类型：
--
作者：
Punyasiri, PAN;Abeysinghe, ISB;Fischer, TC
茶树(Camellia sinensis L.)含有超高含量的(-)-表没食子儿茶素、(-)-表没食子儿茶素、(+)-没食子儿茶素和(+)-儿茶素及其衍生物，对人体健康有积极作用。黄烷醇的健康促进作用，特别是绿茶的作用，是科学和公众关注的问题。此外，它们在防御茶叶病原体方面发挥着至关重要的作用。因此，我们对这些黄酮类化合物的生物合成进行了研究。最近从拟南芥和紫花苜蓿中发现的花青素还原酶在茶叶中具有很高的活性，并从各自的花青素中产生表儿茶素和表没食子儿茶素，从而解释了这些化合物含量很高的原因。二氢黄酮醇4-还原酶/亮色花青素4-还原酶有很强的结合活性，催化儿茶素和没食子儿茶素形成的关键步骤。结合前面酶反应的酶活性和底物特性，阐明了茶叶中最重要的类黄酮的生物合成。(C)2004 Elsevier Inc.保留所有权利。
Leaves of tea (Camellia sinensis L.) contain extraordinary large amounts of (-)-epigallocatechin, (-)-epicatechin, (+)-gallocatechin, and (+)-catechin and derivatives of these compounds that show positive effects on human health. The health-promoting effects of flavan 3-ols, especially those of green tea, are of scientific and public interest. Furthermore, they play a crucial role in defense against pathogens of tea. Therefore, biosynthesis of these flavonoid compounds was investigated. The anthocyanidin reductase enzyme recently described from Arabidopsis and Medicago was shown to be present in tea with very high activity and produces epicatechin as well as epigallocatechin from the respective anthocyanidins, thus explaining the very high contents of these compounds. A strong combined dihydroflavonol 4-reductase/leucoanthocyanidin 4-reductase activity was demonstrated and catalyzes the key steps in catechin and gallocatechin formation. Together with the enzyme activities and substrate specificities of the preceding enzymatic reactions, the biosynthesis of the most prominent flavonoids of tea is elucidated. (C) 2004 Elsevier Inc. All rights reserved.