Synthesis, Metabolism and Compartmentation of Malate in Maize Roots

这个项目的目标是了解基本的 苹果酸代谢在植物细胞中的作用。 13C NMR 光谱学被用来确定 在玉米根尖细胞质和液泡之间的苹果酸。 这些测定与体内和体外的 苹果酸合成，脱羧，液泡 苹果酸的运输和转化为其他代谢物 为了全面了解苹果酸盐的行为， 在细胞内。 这些分析的结果将有助于 （1）确定苹果酸（相对于丙酮酸） 主要代谢产物用于驱动 植物线粒体TCA循环; 2）苹果酸在植物线粒体TCA循环中的作用; 细胞质中PEP羧化酶活性的调节， 3)胞质碳酸氢盐水平和 苹果酸代谢对盐胁迫的响应 苹果酸（Malate）长期以来一直被认为是 作为与以下物质相关的主要中间体化合物的潜力 高等植物细胞中的呼吸和相关代谢。 然而，苹果酸的确切重要性一直没有得到精确的解释。 由于缺乏测量苹果酸的能力， 其在完整细胞内的合成/分解速率。 这个项目使用核磁共振光谱，加上一系列的 更经典的生化分析，来观察水平。 苹果酸在玉米根内的运动速率和方向 提示细胞发展的作用苹果酸的精确图片 在植物呼吸代谢中的作用 更好地了解 苹果酸在植物呼吸作用中的作用， 更清楚地了解哪些因素起作用来调节植物 #21443;，最终提高生产力 *。

The goal of this project is to understand the fundamental role of malate metabolism in plant cells. 13C NMR spectroscopy is being used to determine the compartmentation of malate between cytoplasm and vacuole in maize root tips. These determinations are coupled with in vivo and in vitro measurements of malate synthesis, decarboxylation, vacuolar transport and the conversion of malate to other metabolites to obtain a comprehensive picture of the behavior of malate within the cell. The results of these analyses will help establish 1) the extent to which malate (versus pyruvate) is the major metabolite utilized to drive the operation of the TCA cycle in plant mitochondria, 2) the role of malate in the regulation of PEP carboxylase activity in the cytoplasm and 3) the interplay between cytosolic bicarbonate levels and malate metabolism in response to salt stress.%%% Malic acid (malate) has long been recognized for its potential as a major intermediate compound associated with respiratory and related metabolisms in higher plant cells. However, the exact importance of malate has eluded precise clarification due to a lack of ability to measure malate and its rates of synthesis/breakdown within the intact cell. This project uses NMR spectroscopy, coupled with a series of more classical biochemical assays, to look at the levels. rates and directions of movement of malate within corn root tip cells to develop a precise picture of the role of malate in plant respiratory metabolism. A better understanding of the function of malate in plant respiration should lead to a clearer picture of what factors act to regulate plant respiration and, ultimately, plant productivity.***