Masuda Tatsuru
Graduate School of Arts and Sciences, The University of Tokyo, Komaba 3-8-1, Meguro-ku, Tokyo 153-8902, Japan.
Photosynth Res. 2008 May;96(2):121-43. doi: 10.1007/s11120-008-9291-4. Epub 2008 Feb 14.
In plants, chlorophylls (chlorophyll a and chlorophyll b) are the most abundant tetrapyrrole molecules and are essential for photosynthesis. The first committed step of chlorophyll biosynthesis is the insertion of Mg(2+) into protoporphyrin IX, and thus subsequent steps of the biosynthesis are called the Mg branch. As the Mg branch in higher plants is complex, it was not until the last decade--after many years of intensive research--that most of the genes encoding the enzymes for the pathway were identified. Biochemical and molecular genetic analyses have certainly modified the classic metabolic map of tetrapyrrole biosynthesis, and only recently have the molecular mechanisms of regulatory pathways governing chlorophyll metabolism been elucidated. As a result, novel functions of tetrapyrroles and biosynthetic enzymes have been proposed. In this review, I summarize the recent findings on enzymes involved in the Mg branch, mainly in higher plants.
在植物中，叶绿素（叶绿素a和叶绿素b）是最丰富的四吡咯分子，对光合作用至关重要。叶绿素生物合成的第一个关键步骤是将Mg(2+)插入原卟啉IX中，因此生物合成的后续步骤被称为Mg分支。由于高等植物中的Mg分支很复杂，经过多年的深入研究，直到过去十年才鉴定出该途径中大多数编码酶的基因。生化和分子遗传学分析无疑修改了经典的四吡咯生物合成代谢图，直到最近才阐明了控制叶绿素代谢的调控途径的分子机制。因此，人们提出了四吡咯和生物合成酶的新功能。在这篇综述中，我总结了主要在高等植物中参与Mg分支的酶的最新研究结果。
