BIOCHEMISTRY OF THE 3-METHYLGLUTACONIC ACIDURIAS

3-甲基戊二酸的生物化学

• 批准号: 3246462
• 负责人: RICHARD Ian KELLEY
• 金额: $ 11.47万
• 依托单位: HUGO W. MOSER RES INST KENNEDY KRIEGER
• 依托单位国家: 美国
• 财政年份: 1992
• 资助国家: 美国
• 起止时间: 1992-07-01 至 1995-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/3246462
• 关键词: aminoacid metabolism; animal tissue; coenzyme A; enzyme activity; fatty acid metabolism; human tissue; hydro lyase; inborn metabolism disorder; intracellular transport; isoprenoid; isozymes; leucine; mevalonate; molecular pathology; tissue /cell culture

In recent years, our laboratory and other biochemical genetics units have identified a number of patients who have persistent 3-methylglutaconic aciduria but who do not have an identifiable disturbance in their metabolism of leucine, the presumed precursor of 3-methylglutaconic acid in man. Our further studies of these patients suggest instead that their urinary 3-methylglutaconate derives from the "trans-methyl-glutaconate (mevalonate) shunt, "a little known isoprenoid-related pathway that may be of fundamental importance to our understanding of not only these patients but also regulation of polyisoprenoid and cholesterol metabolism in man. This proposal addresses several questions we seek to answer to be able to understand better the different pathways of 3-methylglutaconic acid metabolism in man. 1) What is the activity of the mevalonate shunt in cultured human fibroblasts, lymphoblasts, and myoblasts? Methods will be developed for measuring overall flux through the shunt and then applied to the study of the activity of the methyl-glutaconate shunt in cultured cells. 2) What is the subcellular localization of the mevalonate shunt? Are there multiple enzymes with the ability to hydrate 3-methylglutaconate or 3- methylglutaconyl-CoA with different subcellular localizations? We will assay subcellular fractions (rat liver, muscle, and fibroblast) for hydratase activity and compare the activities in normal cells with those found in cells from patients with 3-methylglutaconic aciduria. 3) What is the metabolic pathway for the production of 3-methylglutaconate independent of leucine catabolism and the diversion of mevalonate carbon to the synthesis of n-fatty acids? The metabolism of leucine and mevalonate in cultured cells will be traced using various labelling strategies to identify the level(s), synthetic or catabolic, at which isoprenoid carbon is diverted to 3-methylglutaconate. Identified pathways will then be studied in cell lines from patients with leucine-independent 3- methylglutaconic aciduria.

近年来，我室及其他生化遗传学单位 确定了许多患有持续性 3-甲基戊二酸血症的患者 酸尿症，但没有明显的紊乱 亮氨酸的代谢，推测是 3-甲基戊二酸的前体 男人。 我们对这些患者的进一步研究表明，他们的 尿液中的 3-甲基戊二酸源自“反式-甲基-戊二酸” （甲羟戊酸）分流，“一种鲜为人知的类异戊二烯相关途径，可能是 对我们了解这些患者至关重要 还调节人体聚异戊二烯和胆固醇代谢。 该提案解决了我们寻求回答的几个问题，以便能够 更好地了解 3-甲基戊二酸的不同途径 人的新陈代谢。 1) 甲羟戊酸分流在培养人类中的活性是什么 成纤维细胞、淋巴母细胞和成肌细胞？ 将开发方法用于 测量通过分流器的总通量，然后应用于研究 培养细胞中甲基戊二酸分流的活性。 2) 甲羟戊酸分流的亚细胞定位是什么？ 有吗 多种酶能够水合 3-甲基戊二酸或 3- 具有不同亚细胞定位的甲基戊二酰辅酶A？ 我们将 检测亚细胞组分（大鼠肝脏、肌肉和成纤维细胞） 水合酶活性并将正常细胞中的活性与正常细胞中的活性进行比较 在 3-甲基戊二酸尿症患者的细胞中发现。 3) 产生3-甲基戊二酸的代谢途径是什么 独立于亮氨酸分解代谢和甲羟戊酸碳的转移 n-脂肪酸的合成？ 亮氨酸和甲羟戊酸的代谢 将使用各种标记策略来追踪培养细胞中的 确定类异戊二烯碳的合成或分解代谢水平 被转化为3-甲基戊二酸。 确定的路径将被 在来自亮氨酸非依赖性 3- 患者的细胞系中进行了研究 甲基戊烯酸尿症。