Asparagine metabolism and function in nitrogen signaling

种子蛋白质的积累取决于氮对发育中的胚的供应，这影响了碳在不同贮藏产物中的分配。天冬酰胺是高等植物氮素运输的重要形式。天冬酰胺酶被认为在向包括发育中的种子在内的库组织供应氮中起关键作用。这种酶将天冬酰胺分解成天冬氨酸和氨，氨被重新同化并用于合成其他氨基酸。在大豆和谷物中观察到发育中的种子中游离天冬酰胺水平与成熟时的蛋白质含量之间的相关性，这表明天冬酰胺可能作为调节蛋白质积累的代谢物信号发挥作用。本提案的目的是实现一个详细的了解，天冬酰胺catenarase在高等植物，天冬酰胺的功能和感知作为氮代谢信号。包括酶的结构和功能，分子遗传学，转录和代谢产物分析，代谢生物化学的研究方法将被用来解决这个目标。拟议的研究应提高我们的理解的过程中，种子氮供应，并可能导致生物技术策略，以操纵水平的存储产品，无论是提高营养价值或生物工业应用。

Seed protein accumulation is dependent on the supply of nitrogen to the developing embryo, which influences the partitioning of carbon into the different storage products. Asparagine is a key transport form of nitrogen in higher plants. The enzyme asparaginase is hypothesized to play a critical role in the supply of nitrogen to sink tissues including developing seeds. This enzyme breaks down asparagine into aspartate and ammonia, which is re-assimilated and used in the synthesis of other amino acids. A correlation between free asparagine levels in developing seeds and protein content at maturity has been observed in soybean and cereals, suggesting a possible role of asparagine as a metabolite signal regulating protein accumulation. The objectives of this proposal are to achieve a detailed understanding of asparagine catabolism in higher plants, and of asparagine function and perception as a nitrogen metabolite signal. Approaches including the study of enzyme structure and function, molecular genetics, transcript and metabolite profiling, and metabolic biochemistry will be used to address this goal. The proposed research should improve our understanding of the process of seed nitrogen supply, and may lead to biotechnological strategies to manipulate the levels of storage products, either to enhance nutritional value or for bio-industrial applications.