Development and validation of metabolic models to simulate the operation and interaction of antioxidant systems

抗氧化剂系统提供针对由于环境压力而产生的活性氧（ROS）的保护。它们还控制H2 O2和O2的浓度，这两种物质作为信号中间体在防御和生长之间切换代谢。由于抗氧化系统的复杂性及其在所有亚细胞区室中的存在，目前还不清楚这些系统如何在高度动态和协调的网络中发挥作用以调节ROS的稳态水平。该提案的目标是通过基于计算机的建模和验证实验来增加对抗氧化剂网络的理论理解。为此，我们将开发基于抗氧化系统的生化和物理化学性质的模块，以模拟不同亚细胞区室中的氧化还原反应。这些模块将被连接到帐户的运输。为了验证，将使用两种方法：（a）通过分析叶绿体基因敲除突变体获得的数据进行模型调整，拟南芥中抗坏血酸-谷胱甘肽循环的线粒体和胞质酶，由相关项目中的美国合作伙伴提供，和（B）测试关于抗坏血酸/谷胱甘肽循环的选定模型预测。通过使用放射性示踪剂以及使用TEM-EDX在不同亚细胞区室中绘制和定量H2 O2代谢。

Antioxidant systems provide protection against reactive oxygen species (ROS) produced as a are result of environmental stresses. They also control the concentrations of H2O2 and O2- which play roles as signaling intermediates to switch the metabolism between defence and growth. Because of the complexity of antioxidant systems and their presence in all subcellular compartments, it is not yet understood, how these systems function in a highly dynamic and co-ordinated network to regulate the steady state levels of ROS. The goal of this proposal is to increase the theoretical understanding of antioxidant networks by means of based-computer modeling and validation experiments. For this purpose, we will develop modules based on biochemical and physico-chemical properties of antioxidant sytems to simulate redox-reactions in differnt subcellular compartments. These modules will be connected to account for transport. For validation, two approaches will be used: (a) Model adjustment by data obtained by analysis of knock-out mutants of chloroplastic, mitochondrial and cytosolic enzymes of the ascorbate-glutathione cycle in Arabidopsis provided by USA-partners in an associated project and (b) Testing selected model predictions with respect to ascorbate/H2O2 metabolism by use of radiotracers and by mapping and quantification of H2O2 in different subcellular compartments using TEM-EDX.