STUDIES OF CARDIAC METABOLISM BY 13C AND 31P NMR

通过 13C 和 31P NMR 研究心脏代谢

• 批准号: 3340788
• 负责人: JOHN R. WILLIAMSON
• 金额: $ 10.53万
• 依托单位: UNIVERSITY OF PENNSYLVANIA
• 依托单位国家: 美国
• 财政年份: 1983
• 资助国家: 美国
• 起止时间: 1983-07-01 至 1987-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/3340788
• 关键词: Krebs' cycle; aspartate; aspartate transaminase; carbohydrate metabolism; cell free system; citrate synthase; dicarboxylate; heart metabolism; malate dehydrogenase; malates; mitochondria; myocardial ischemia /hypoxia; nuclear magnetic resonance spectroscopy; oxaloacetates; oxoglutarate dehydrogenase; perfusion; propionates; radiotracer

The major goal of this project is to take advantage of the recent advances made in the field of 31p and 13C nuclear magnetic resonances (NMR) spectroscopy to study the energetics and metabolism of perfused rat hearts under different conditions of substrate supply and work. Emphasis will be given to the use of 13C-enriched substrates to study regulation of the citric acid cycle, its interactions with the malate-asparate cycle and mechanisms for increasing or decreasing net pool sizes of citric acid cycle intermediates. 13C NMR spectra will be obtained using both intact hearts and perchloric acid extracts. The latter will also be used for enzymatic assay of metabolites to aid identification and quantitation of resonances obtained from individual 13C-labeled carbon atoms from the 13C spectra. The information provided from 13C specific labeling patterns of intermediates, together with knowledge of their total pool sizes as determined by metabolic analyses, will be used to construct a flux model of the citric acid cycle and interrelated transamination steps. The model will be used to test various hypotheses concerning regulation of flux in the citric acid cycle under different conditions of substrate supply and work output of the heart during the steady state as well as transition states when cycle flux is nonuniform. The following major specific aims will be addressed. 1. Identification of rate-controlling steps in the citric acid cycle and assessment of enzyme control strengths by inhibitor titration studies. 2. Assessment of the existence and metabolic significance of metabolite compartmention and substrate channeling. 3. Effects of varying flux rates through the malate-asparate cycle on the regulation of flux through citrate syntase, Alpha-ketoglutarate dehydrogenase and asparate aminotransferase. 4. Investigation of the mechanisms responsible for causing net changes of the tissue contents of citric acid cycle intermediates. 5. Effects of acetoacetate in the absence and presence of propionate on flux through succinate thiokinase and regulation of the citric acid cycle from Alpha-keto-glutarate to malate. 6. Investigation of citric acid cycle function in reoxygenated post-ischemic hearts.

该项目的主要目标是利用最近的进步 在31p和13c核磁共振（NMR）的领域制造 研究灌注大鼠心脏的能量和代谢的光谱学 在基板供应和工作的不同条件下。 重点将是 使用使用13C富集的底物研究调节 柠檬酸循环，其与苹果酸摩尔酸酯周期的相互作用和 增加或减少柠檬酸周期净池尺寸的机制 中间人。 使用完整的心脏将获得13C NMR光谱 和氯酸提取物。 后者也将用于酶促 代谢物的测定以帮助识别和定量共振 从13C光谱的单个13C标记的碳原子中获得。 从13C特定的标签模式提供的信息 中间体，以及他们的总池大小的知识 通过代谢分析确定，将用于构建 柠檬酸循环和相互关联的跨跨步骤。 模型 将用于测试有关调节通量的各种假设 在底物供应不同条件下的柠檬酸周期和 稳定状态和过渡期间心脏的工作输出 何时循环通量不均匀。 以下主要特定目标 将被解决。 1。识别速率控制步骤 柠檬酸循环和抑制剂酶控制强度的评估 滴定研究。 2。评估存在和代谢 代谢物隔室和底物通道的重要性。 3。 通过苹果酸 - 帕拉特循环的变化速度对变化的影响对 调节通过柠檬酸含量酶，α-酮戊二酸的通量调节 脱氢酶和透明度氨基转移酶。 4。调查 负责引起组织内容净变化的机制 柠檬酸循环中间体。 5。乙酸乙酸酯在 通过琥珀酸酯硫代酶的通量不存在和存在丙酸酯和 调节柠檬酸周期从α-酮谷氨酸到苹果酸酯。 6。柠檬酸周期功能的研究 缺血后的心。