Süssenbacher Iris, Hörtensteiner Stefan, Kräutler Bernhard
Institut für Organische Chemie und Centrum für Molekulare Biowissenschaften, Universität Innsbruck, Innrain 80/82, 6020 Innsbruck (Austria).
Institut für Pflanzenbiologie, Universität Zürich, Zollikerstrasse 107, 8008 Zürich (Switzerland).
Angew Chem Int Ed Engl. 2015 Nov 9;54(46):13777-81. doi: 10.1002/anie.201506299. Epub 2015 Oct 1.
Chlorophyll breakdown in higher plants occurs by the so called "PaO/phyllobilin" path. It generates two major types of phyllobilins, the characteristic 1-formyl-19-oxobilins and the more recently discovered 1,19-dioxobilins. The hypothetical branching point at which the original 1-formyl-19-oxobilins are transformed into 1,19-dioxobilins is still elusive. Here, we clarify this hypothetical crucial transition on the basis of the identification of the first natural 1,19-dioxobilin-type fluorescent chlorophyll catabolite (DFCC). This transient chlorophyll breakdown intermediate was isolated from leaf extracts of Arabidopsis thaliana at an early stage of senescence. The fleetingly existent DFCC was then shown to represent the direct precursor of the major nonfluorescent 1,19-dioxobilin that accumulated in fully senescent leaves.
高等植物中的叶绿素分解通过所谓的“PaO/叶胆素”途径发生。它产生两种主要类型的叶胆素，即特征性的1-甲酰基-19-氧代胆素和最近发现的1,19-二氧代胆素。原始的1-甲酰基-19-氧代胆素转化为1,19-二氧代胆素的假设分支点仍然难以捉摸。在此，我们基于对首个天然1,19-二氧代胆素型荧光叶绿素分解代谢物（DFCC）的鉴定，阐明了这一假设的关键转变。这种短暂的叶绿素分解中间体是在衰老早期从拟南芥叶片提取物中分离出来的。随后发现，短暂存在的DFCC代表了在完全衰老叶片中积累的主要非荧光1,19-二氧代胆素的直接前体。
