Oster U, Tanaka R, Tanaka A, Rüdiger W
Institute of Botany, University of Munich, Menzinger Str. 67, D-80638 Munich, Germany, andInstitute of Low Temperature Science, Hokkaido University, N19W8 Sapporo, Japan.
Plant J. 2000 Feb;21(3):305-10. doi: 10.1046/j.1365-313x.2000.00672.x.
Chlorophyll (Chl) biosynthesis and degradation are the only biochemical processes on Earth that can be directly observed from satellites or other planets. The bulk of the Chls is found in the light-harvesting antenna complexes of photosynthetic organisms. Surprisingly little is known about the biosynthesis of Chl b, which is the second most abundant Chl pigment after Chl a. We describe here the expression and properties of the chlorophyllide a oxygenase gene (CAO) from Arabidopsis thaliana, which is apparently the key enzyme in Chl b biosynthesis. The recombinant enzyme produced in Escherichia coli catalyses an unusual two-step oxygenase reaction that is the 'missing link' in the chlorophyll cycle of higher plants.
叶绿素（Chl）的生物合成与降解是地球上唯一能从卫星或其他行星上直接观测到的生化过程。大部分叶绿素存在于光合生物的捕光天线复合体中。令人惊讶的是，人们对叶绿素b的生物合成了解甚少，叶绿素b是仅次于叶绿素a的第二丰富的叶绿素色素。我们在此描述了来自拟南芥的叶绿素酸酯a加氧酶基因（CAO）的表达及特性，该基因显然是叶绿素b生物合成中的关键酶。在大肠杆菌中产生的重组酶催化一种不同寻常的两步加氧酶反应，这是高等植物叶绿素循环中“缺失的环节”。
