A Developmental Study of Essential Amino Acid Biosynthesis in Chloroplasts

叶绿体必需氨基酸生物合成的进展研究

• 批准号: 8904262
• 负责人: William Mills
• 金额: $ 21万
• 依托单位: University of Houston - Clear Lake
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 1989
• 资助国家: 美国
• 起止时间: 1989-09-01 至 1993-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=8904262&HistoricalAwards=false
• 关键词: Developmental; Study; Essential; Amino; Acid

This project focuses on the developmental regulation of essential aspartate-family amino acid metabolism in chloroplasts of higher plants. The hypothesis being tested is that the following parameters will be tested to determine how they vary during leaf development: 1) the level and intracellular distributions of amino acids, 2) the permeability of the chloroplast envelope to amino acids and 3) the activities of key enzymes of essential amino acid production. Purified chloroplasts prepared from leaves of barley plants at various stages of development are used to determine concentrations of amino acids in chloroplasts and other cellular compartments throughout development, to measure the transport of aspartic acid and the metabolically related amino acids, lysine, threonine, methionine and isoleucine, into chloroplasts from leaves of varying ages, and to isolate the enzymes aspartate kinase, homoserine dehydrogenase and dihydrodipicolinate synthetase from plastids of different age tissues and relative catalytic activities. Antibodies also will be raised to the enzymes and variations in enzyme levels will be confirmed by immunological methods. In the last decade it has become clear that the chloroplast is the main site, if not the sole site, for the biosynthesis of the nutritionally essential aspartate-family amino acids in plant leaves. During the development of plant leaves, the requirement for the production of these and other amino acids changes. This research explores whether the capacity of chloroplasts to synthesize the essential aspartate-derived amino acids varies during leaf development, so that chloroplast development and its regulation can be better understood. These studies will further provide information regarding the nature and regulation of essential amino acid biosynthesis. Given that deficiency of two of the aspartate-derived amino acids is a main factor contributing to human malnutrition, new information regarding the regulation of their synthesis is of particular interest.

本项目主要研究人类发育过程中 高等植物叶绿体中谷氨酸家族氨基酸的代谢 植物 正在测试的假设是， 参数将进行测试，以确定它们如何变化， 发展：1）水平和细胞内分布 氨基酸，2）叶绿体被膜的渗透性， 3）必需氨基酸关键酶活性 氨基酸生产 纯化的叶绿体由 使用处于不同发育阶段的大麦植物的叶子， 确定叶绿体中氨基酸的浓度， 在整个发育过程中， 天冬氨酸的转运和代谢相关的 氨基酸，赖氨酸，苏氨酸，蛋氨酸和异亮氨酸， 叶绿体从不同年龄的叶片，并分离 天冬氨酸激酶、高丝氨酸脱氢酶和 不同年龄质体二氢吡啶二羧酸合成酶 组织和相关催化活性。 抗体也将 酶水平的变化将被提高， 免疫学方法证实。 在过去的十年里，人们已经清楚地认识到，叶绿体是 主要的网站，如果不是唯一的网站，为生物合成的 植物必需氨基酸 叶子 在植物叶片的发育过程中， 产生这些和其他氨基酸的变化。 这 研究探讨了叶绿体的能力， 合成必需的谷氨酸衍生氨基酸的方法不同 在叶的发育过程中，叶绿体的发育及其 可以更好地理解规则。 这些研究将进一步 提供关于下列事项的性质和管制的资料： 必需氨基酸生物合成 鉴于两个缺陷 谷氨酸衍生的氨基酸是一个主要因素 导致人类营养不良，有关 它们的合成的调节特别令人感兴趣。