PROLINE METABOLISM/REGULATION OF PURINES/ENERGY TRANSFER

我们建议研究脯氨酸的可能作用， 调节能量生成的代谢系统， 生物合成途径和介导室间 能量转移 基于对红细胞的研究， 肝细胞，似乎吡咯啉-5-羧酸还原酶 (PCR)活性可调节戊糖磷酸途径活性 并导致嘌呤核苷酸的从头刺激 生物合成 此外，PCR和脯氨酸氧化酶（ProOx）可以是 参与细胞质氧化还原电位转化为能量的过程 利用细胞器。 由于异常高水平的 结核中的PCR和嘌呤生物合成活性， 类杆菌中的ProOx（缺乏能量消耗区室） 糖酵解能力）和极高的能量通量 从细胞质转移到类菌体、大豆根瘤中 max是一个很好的模型系统来研究所提出的 PCR和ProOx在房室间能量传递中的作用 和嘌呤核苷酸生物合成。 实验计划是 旨在研究这两种不同的，但不是相互的 PCR和ProOx的排他性功能（即嘌呤的调节） 核苷酸生物合成和细胞器之间的能量转移） 上面提出的。 具体目标是：1）本地化， 表征PCR、ProOx和其他酶的活性， 脯氨酸代谢; 2）确定 PCR活性和嘌呤核苷酸合成; 3）确定作用 脯氨酸在氧化还原电位的室间转移中的作用; 4)为了证明PCR的生理学意义， 完整组织中的ProOx。 实验方法包括 PCR和ProOx的生化表征，亚细胞 分馏和示踪研究。 获得的结果将 有助于我们理解细胞的一般机制， 以及亚细胞能量转移和代谢调节 真核生物

We propose to examine the possible role of the proline metabolizing system in regulating energy-generating and biosynthetic pathways and in mediating intercompartmental energy transfer. Based on studies with erythrocytes and hepatocytes, it appears that pyrroline-5-carboxylate reductase (PCR) activity may modulate pentose phosphate pathway activity and result in the stimulation of de novo purine nucleotide biosynthesis. In addition PCR and proline oxidase (ProOx) may be involved in transfer of cytoplasmic redox potential into energy- utilizing organelles. Because of the uncommonly high levels of PCR and purine biosynthetic activity in nodules, the presence of ProOx in bacteroids (energy-consuming compartments lacking glycolytic capability), and the extremely high flux of energy transfer from the cytoplasm into bacteroids, nodules of Glycine max are an excellent model system to investigate the proposed roles of PCR and ProOx in intercompartmental energy transfer and purine nucleotide biosynthesis. The experimental plan is designed to examine the two different, but not mutually exclusive, functions of PCR and ProOx (i.e. regulation of purine nucleotide biosynthesis and energy transfer between organelles) proposed above. The specific objectives are: 1) to localize and characterize activities of PCR, ProOx, and other enzymes of proline metabolism; 2) to determine the relationship between PCR activity and purine nucleotide synthesis; 3) to define the role of proline in intercompartmental transfer of redox potential; and 4) to demonstrate the physiological significance of PCR and ProOx in intact tissues. The experimental approach involves biochemical characterization of PCR and ProOx, subcellular fractionation and tracer studies. The results obtained will contribute to our understanding of general mechanisms of cellular and subcellular energy transfer and metabolic regulation in eucaryotes.