NOREPINEPHRINE BIOSYNTHESIS--ROLE OF ASCORBATE

中枢儿茶酚胺类神经递质和神经肽 外周神经激素系统可能与临床疾病有关 如高血压、心脏异常和神经功能障碍 比如精神分裂症和其他精神疾病。因此， 对体内儿茶酚胺类神经递质的认识 神经肽激素在分子水平上的生物合成将是重要的 以了解这些疾病的病因并最终 开发有效的治疗剂。抗坏血酸的作用 (ASC)在儿茶酚胺和神经递质的生物合成中 因此，神经肽激素在整个神经内分泌功能中 得到了广泛的认可。由于大量的神经内分泌分泌囊泡 肾上腺髓质或其他内分泌腺不会将ASC 囊泡膜，跨膜的血红蛋白，细胞色素b561， 拟负责调剂必要的减量 儿茶酚胺生物合成酶的等价物，多巴胺β- 单加氧酶(DBM)和神经肽加工终端酶， 胞浆池中的肽基α-羟基单加氧酶(PHM) ASC.尽管，最近的努力是针对 在分子水平上理解这一复杂的电子转移过程 水平，与儿茶酚胺和神经肽的生物合成有关， 这些努力的进展受到了复杂性和 细胞内和细胞外因素影响的多样性。整体而言 我们的计划的目标是明确人类免疫缺陷的分子机制。 还原当量从胞浆ASC向胞内转移的研究 神经内分泌颗粒经仔细检查氧化还原 途径中各种蛋白质的相互作用。我们正在提议 通过检查还原剂的相互作用来实现这一目标， 阴离子酶激活剂和其他含有DBM的底物，特别是在 不同合成方法与活性中心铜氧化还原中心的关系 探头和光谱技术，并将类似研究扩展到PHM。 同时，我们将提纯并进一步表征新发现的 酸性库珀蛋白作为细胞色素b561和DBM之间的氧化还原介体 (和PHM)。我们将研究单向运动的分子机制。 电子在B561颗粒膜上的传输 生化和生物物理技术。最后，所有的信息都将 结合起来提出了两者在体内还原的分子模型 DBM和PHM。

The catecholamine neurotransmitters and neuropeptides in the central and peripheral neurohormonal system may be implicated in clinical disorders such as hypertension, cardiac abnormalities and neurological dysfunctions like schizophrenia and other mental illnesses. Therefore, the understanding of the in vivo catecholamine neurotransmitter and neuropeptide hormone biosynthesis at the molecular level will be important for the understanding of the etiology of these diseases and eventual development of effective therapeutic agents. The role of ascorbic acid (Asc) in the biosynthesis of both catecholamine neurotransmitters and neuropeptide hormones and thus, in overall neuroendocrine functions has been well recognized. Since numerous neuroendocrine secretory vesicles of the adrenal medullae or other endocrine glands do not transfer Asc across the vesicle membrane, the transmembrane hemoprotein, cytochrome b561, is proposed to be responsible for transferring the necessary reducing equivalents for both the catecholamine biosynthetic enzyme, dopamine beta- monooxygenase (DbM), and the neuropeptide processing terminal enzyme, peptidyl alpha-hydroxylating monooxygenase (PHM), from the cytosolic pool of Asc. Although, recent efforts have been directed towards the understanding of this intricate electron transfer process at the molecular level, in relation to catecholamine and neuropeptide biosynthesis, progress of these efforts has been hampered by the complexity and the diversity of the effects of intra-and extra-cellular factors. The overall objective of our program is to define the molecular mechanism of the transfer of reducing equivalents from the cytosolic Asc to the interior of the neuroendocrine granule by careful examination of the redox interactions of various proteins in the pathway. We are proposing to achieve this objective by examining the interaction of the reductant, anion enzyme activators, and other substrates with DbM especially in relation to the active site copper redox centers using various synthetic probes and spectroscopic techniques and to extend similar studies to PHM. In parallel, we will purify and further characterize the newly identified acidic cooper protein as a redox mediator between cytochrome b561 and DbM (and PHM). We will examine the molecular mechanism of the unidirectional electron transport across the granule membrane through b561 using biochemical and biophysical techniques. Finally all the information will be combined to propose a molecular model for the in vivo reduction of both DbM and PHM.