ROLE OF NADH-FUMARATE REDUCTASE IN TRYPANOSOMA BRUCEI

NADH-富马酸还原酶在布氏锥虫中的作用

• 批准号: 2067586
• 负责人: JULIO F TURRENS
• 金额: $ 9.72万
• 依托单位: UNIVERSITY OF SOUTH ALABAMA
• 依托单位国家: 美国
• 财政年份: 1992
• 资助国家: 美国
• 起止时间: 1992-06-01 至 1995-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/2067586
• 关键词: Trypanosoma; carbohydrate metabolism; cellular respiration; enzyme activity; enzyme inhibitors; enzyme substrate; intracellular parasitism; nicotinamide adenine dinucleotide; protein purification; succinates

DESCRIPTION (Adapted from Applicant's Abstract): The trypanosomatids Trypanosoma cruzi and the T. brucei group cause Chagas' disease and African sleeping sickness, respectively. Little effort is being placed on identifying new targets for developing a rational therapy against these diseases. The applicant has found that several strains of Trypanosoma contain an enzyme not present in mammals (NADH-fumarate reductase) which produces succinate, and allows a section of the Krebs' cycle to operate in reverse. In many trypanosomatids, succinate has a dual role, as a metabolic end product secreted to the extracellular environment and as an important respiratory substrate for cells with a complete respiratory chain (epimastigotes or procyclic trypomastigotes). The applicant believes succinate has a central role in intermediate metabolism of T. brucei, and intends to characterize the metabolic role of fumarate reductase as a succinate-producing enzyme. This enzyme is also present in bloodstream forms (in which the respiratory chain is not active), but its physiological role in these forms is unknown. Fumarate reductase was initially thought to be associated to the membrane fraction. The applicant has found, however, that this enzyme may be solubilized at high ionic strength, a first step towards its purification. The applicant proposes to: 1) purify and study this enzyme from T. brucei trypomastigotes and from procyclic trypomastigotes; 2) characterize four available inhibitors of the purified enzyme; 3) determine the metabolic function of this enzyme in the intermediate metabolism of T. brucei procyclic trypomastigotes by monitoring substrate accumulation, succinate production and NAD(P)H oxidation with glucose and proline as substrates, and 4) investigate its intracellular localization.

描述（改编自申请人的摘要）：锥虫 克氏锥虫和T.布氏菌群引起恰加斯病， 非洲昏睡病。 几乎没有努力放在 为开发针对这些疾病的合理疗法确定新的靶点 疾病 申请人已经发现，几种锥虫属菌株 含有哺乳动物中不存在的酶（NADH-延胡索酸还原酶）， 产生琥珀酸，并允许克雷布斯循环的一部分在 反面. 在许多锥虫中，琥珀酸具有双重作用，作为 代谢终产物分泌到细胞外环境中，并作为 重要的呼吸基质细胞具有完整的呼吸 链（上鞭毛体或原环锥鞭毛体）。 申请人 认为琥珀酸在T. 布氏杆菌，并打算表征富马酸盐的代谢作用 还原酶作为琥珀酸生产酶。 这种酶也存在于 血流形成（其中呼吸链不活跃），但其 这些形式的生理作用是未知的。 富马酸还原酶是 最初被认为与膜部分有关。 的 然而，申请人已经发现，这种酶可以在高浓度下溶解， 离子强度，这是提纯的第一步。 申请人 提出：1）从T.布氏 trypomastigotes和procyclic trypomastigotes; 2）表征四个 纯化酶的可用抑制剂; 3）确定代谢产物 该酶在T.布氏 通过监测底物积累的前环锥鞭毛体，琥珀酸 以葡萄糖和脯氨酸为底物， （4）研究其细胞内定位。