4-Hydroxyphenylpyruvate Dioxygenase and Tyrosinemia

4-羟基苯丙酮酸双加氧酶和酪氨酸血症

• 批准号: 6744999
• 负责人: GRAHAM Rodney MORAN
• 金额: $ 6.13万
• 依托单位: UNIVERSITY OF WISCONSIN MILWAUKEE
• 依托单位国家: 美国
• 财政年份: 2002
• 资助国家: 美国
• 起止时间: 2002-04-15 至 2006-02-28
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6744999
• 关键词: aminoacid metabolism; enzyme activity; enzyme inhibitors; enzyme mechanism; enzyme structure; enzyme substrate analog; enzyme substrate complex; iron sulfur protein; oxygenases; tyrosinemias

DESCRIPTION (provided by applicant): Iron-dependent non-heme oxygenases are the specific focus of this research. These enzymes catalyze vital metabolic and catabolic reactions throughout mammalian metabolism. The initial intent is to develop a fundamental understanding of the chemistry of these enzymes by the identification of the transient oxygen intermediates that are generated during catalysis. The long-term objective is to find evidence for the geometry of transition states for specific catalytic steps such that stable transition state mimics can be developed as inhibitory therapeutic agents to control the flux through key metabolic pathways. Initially, the enzyme 4-hydroxyphenylpyruvate dioxygenase (HPPD) has been selected for investigation. This enzyme exemplifies many of the catalytic functions of other FeII-dependent non-heme dioxygenases such as aromatic oxygenation, oxidative decarboxylation and substituent migration. Furthermore, it is one of the few alpha-keto acid-dependent oxygenases for which the crystal structure is known. Moreover, it has become a paradigm example of the ability to alleviate metabolic disorders through selective enzymatic inhibition. Type 1 Tyrosinemia, is caused by a deficiency of active fumarylacetoacetase, an enzyme that catalyzes the final step in the pathway for the catabolism of tyrosine. In the absence of treatment this disease is often fatal in the first year of life and always prior the completion of the first two decades. It is known, however, that the inhibition of HPPD which catalyzes the second step of this pathway is, in most cases, an effective treatment for type 1 Tyrosinemia. Part of the intent of this research is that the mechanism of this inhibition be understood in the context of catalytic events of the enzyme. The experimental approach will be to combine steady state and pre-steady state analyses with the selective use of substrate analogs, isotopic labels and mutagenesis and crystallography to test mechanistic hypotheses on the basis of rate constant modulation and structure.

描述（申请人提供）：铁依赖性的非血红素氧酶是 这项研究的具体重点。这些酶催化了重要的代谢和 整个哺乳动物代谢的分解代谢反应。最初的意图是 通过对这些酶的化学的基本了解 鉴定在期间生成的瞬态氧中间体 催化。长期目标是找到证据的几何形状 特定催化步骤的过渡状态，使得稳定过渡 状态模拟物可以作为抑制性治疗剂来发展 通过关键代谢途径的通量。最初，酶 已经选择了4-羟基苯基丙酮酸二加氧酶（HPPD）进行研究。 这种酶体现了其他FEII依赖性的许多催化功能 非血红素二氧化激酶，例如芳族氧合，氧化脱羧化 和取代基迁移。此外，它是为数不多的α-酮之一 已知晶体结构的酸依赖性氧酶。而且， 它已成为减轻新陈代谢能力的范式例子 通过选择性酶抑制作用。 1型酪氨酸血症是由活性富马乙酰丙酰乙酸酶的缺乏引起的 促进途径的最后一步的酶 酪氨酸。在没有治疗的情况下，这种疾病通常是致命的 生命的一年，总是在前二十年完成之前完成。这是 然而，已知抑制HPPD的抑制是催化第二步的HPPD 在大多数情况下，该途径是1型酪氨酸血症的有效治疗方法。 这项研究目的的一部分是，这种抑制的机制是 在酶的催化事件的背景下理解。实验 方法是将稳态和稳态分析与 选择性使用底物类似物，同位素标签和诱变和 晶体学以基于速率常数检验机械假设 调制和结构。