Basset Gilles J, Latimer Scott, Fatihi Abdelhak, Soubeyrand Eric, Block Anna
Horticultural Sciences Department, University of Florida, Gainesville, FL 32608, United States.
Institut Jean-Pierre Bourgin, UMR1318 INRA-AgroParisTech, Versailles, France.
Mini Rev Med Chem. 2017;17(12):1028-1038. doi: 10.2174/1389557516666160623082714.
Phylloquinone is a prenylated naphthoquinone that is synthesized exclusively by plants, green algae, and some species of cyanobacteria, where it serves as a vital electron carrier in photosystem I and as an electron acceptor for the formation of protein disulfide bonds.
In humans and other vertebrates, phylloquinone plays the role of a vitamin (vitamin K1) that is required for blood coagulation and bone and vascular metabolism. Phylloquinone from green leafy vegetables and vegetable oil represents the major dietary source of vitamin K for humans.
In recent years, reverse genetics and biochemical approaches using the model plant Arabidopsis thaliana have shown that phylloquinone biosynthesis in plants involves paralogous and multifunctional enzymes, a compartmentation of the corresponding pathway in plastids and peroxisomes, and trafficking of some biosynthetic intermediates within plastids themselves. Furthermore, phylloquinone biosynthetic intermediates create crucial metabolic branch-points with other plastid-synthesized metabolites such as chlorophylls, tocopherols and salicylate.
RESULTS & CONCLUSION: This review presents an update on recent studies of the central role of plastids in the biosynthesis of phylloquinone, in particular on the discovery of novel enzymatic steps that are likely paradigms for phylloquinone and menaquinone (vitamin K2)-synthesizing organisms alike.
叶绿醌是一种异戊烯基化萘醌，仅由植物、绿藻和某些蓝细菌物种合成，在这些生物中它作为光系统I中的重要电子载体以及蛋白质二硫键形成的电子受体。
在人类和其他脊椎动物中，叶绿醌起着维生素（维生素K1）的作用，是血液凝固以及骨骼和血管代谢所必需的。绿叶蔬菜和植物油中的叶绿醌是人类维生素K的主要饮食来源。
近年来，利用模式植物拟南芥的反向遗传学和生化方法表明，植物中叶绿醌的生物合成涉及旁系同源和多功能酶、相应途径在质体和过氧化物酶体中的区室化，以及一些生物合成中间体在质体自身内部的运输。此外，叶绿醌生物合成中间体与其他质体合成的代谢物如叶绿素、生育酚和水杨酸形成关键的代谢分支点。
本综述介绍了质体在叶绿醌生物合成中的核心作用的最新研究进展，特别是关于可能是叶绿醌和甲萘醌（维生素K2）合成生物体范例的新酶促步骤的发现。
