Regulation of Ornithine Transcarbamylase and Its Function inPlant Nitrogen Metabolism

几种主要的氮代谢途径受到精氨酸生物合成途径活动的影响。在植物中，人们对精氨酸生物合成的代谢调控知之甚少。同样，调节鸟氨酸转氨基甲酰基酶（OTC）活性的机制也是未知的，这种酶催化精氨酸生物合成途径的第一步。在不同的生理条件下，氮分配到精氨酸、嘧啶核苷酸和多胺生物合成途径的动态将被研究，使用放射性标记的前体和这些途径的特异性抑制剂。这些实验将在两个模型系统（含Ti质粒pGV3850的野碱合成酶转化的烟草和渗透胁迫的燕麦叶）中进行，其中组织中较高的精氨酸利用率将支持精氨酸途径和OTC活性的升高。当植物受到胁迫时，植物体内的氮代谢受到影响。本项目研究多胺生物合成途径及其在应激条件下的调控。这将有助于更好地了解工厂内发生的变化。干预措施将有可能保护植物的生产力

Several of the major nitrogen metabolic pathways are impacted by activities of the arginine biosynthetic pathway. In plants, little is known regarding the metabolic regulation of arginine biosynthesis. Similarly, mechanisms regulating the activity of ornithine transcarbamylase (OTC), the enzyme that catalyzes the first committed step in the arginine biosynthetic pathway, are unknown. The dynamics of nitrogen allocation to the arginine, pyrimidine nucleotide and polyamine biosynthetic pathways will be investigated under different physiological conditions, using radiolabeled precursors and specific inhibitors of these pathways. These experiments will be carried out in two model systems (tobacco transformed with the nopaline synthase containing Ti plasmid pGV3850 and osmotically-stressed oat leaf) in which high rates of arginine utilization in the tissue would be expected to support elevated arginine pathway and OTC activities.%%% Nitrogen metabolism in plants is affected when the plant is stressed. This project investigates the pathway of polyamine biosynthesis and how it is regulated during stress. This will lead to a better understanding of the changes taking place in the plant. Interventions will be possible to protect plant productivity.***//