BIOSYNTHESIS OF TETRAHYDROBIOPTERIN IN DROSOPHILA MELANOGASTER

四氢生物蝶呤（H4 B）合成中的遗传变异已被证实。 与几种人类神经系统疾病相关， 苯丙酮尿症、帕金森病和阿尔茨海默病。 的 H4 B对这些过程的重要性在于它作为一种必需的 酪氨酸和色氨酸羟化酶的辅因子，参与酪氨酸和色氨酸羟化酶的酶， 分别合成儿茶酚胺和血清素。 BH 4也是 一氧化氮合酶所需的一氧化氮， 一种有效的细胞信号分子，参与控制 哺乳动物的血管扩张 BH 4在真核生物中结构保守， 这显然是其生物合成的途径。 的生物合成 BH 4，在昆虫、大鼠和人类等多种生物体中， 需要GTP环化水解酶，1，乙酰基-H4蝶呤还原酶， BH 4的生物合成仍不清楚。 拟议的研究包括 纯化和生物化学特性的果蝇， H4蝶呤还原酶。 纯化的酶将用于提高多克隆 抗血清 α-异戊酰-H4蝶呤还原酶抗体将用于 分离编码该酶的分子克隆，并在其他生物化学中 表征，例如乙酰基-H4蝶呤还原酶的定位 在原地。 一个经典的突变体筛选分离的一个异戊酰- H4蝶呤还原酶突变体被提出作为一个独立的本科 学生项目。 虽然人类H4 B的几种“先天性错误” 生物合成存在（GTP）环化水解酶1，异戊酰-H4蝶呤合酶， 二氢蝶啶还原酶），没有已知的异戊酰-H4蝶呤还原酶 突变 果蝇是唯一有直接策略的生物 为了获得这样的突变体， 还原酶的途径导致眼睛色素合成。 长期目标 这些研究的目的是帮助了解终端 BH 4在果蝇和其他高等生物中的生物合成步骤。

Genetic variations in the synthesis of tetrahydrobiopterin (H4B) have been associated with several human neurological disorders such as atypical phenylketonuria, Parkinson's disease, and Alzheimer's disease. The importance of H4B to these processes is found in its role as an essential cofactor for tyrosine and tryptophan hydroxylase, enzymes involved in the synthesis of catecholamines and serotonin, respectively. BH4 is also required by nitric oxide synthase in the synthesis of nitric oxide, a potent cell-signaling molecule which is involved in the control of vasodilation in mammals. BH4 is structurally conserved among eukaryotes, as is apparently the pathway for its biosynthesis. The biosynthesis of BH4, in organisms as diverse as insects, rats and humans, minimally requires GTP cyclohydrolase, 1, pyruvoyl-H4pterin reductase ina the biosynthesis of BH4 remains unclear. The proposed research includes the purification and biochemical characterization of the Drosophila pyruvoyl- H4pterin reductase. The purified enzyme will be used to raise polyclonal antisera. The alpha-pyruvoyl-H4pterin reductase antibody will be used to isolate a molecular clone encoding for the enzyme and in other biochemical characterizations such as the localization of pyruvoyl-H4pterin reductase in situ. A classical mutant screen for the isolation of a pyruvoyl- H4pterin reductase mutant is proposed as an independent undergraduate student project. Although several human "in born errors" of H4B biosynthesis exist (GTP) cyclohydrolase 1, pyruvoyl-H4pterin synthase, dihydropteridine reductase) there is no known pyruvoyl-H4pterin reductase mutation. Drosophila is the only organism where there is a direct strategy for obtaining such a mutant, due to the involvement of pyruvoyl-H4pterin reductase in pathways leading to eye pigment synthesis. The long term goal of these studies is to contribute to the understanding of the terminal steps of BH4 biosynthesis in Drosophila and other higher organisms.