Characterization and Localization of Purine Synthesis Enzymes from Soybean Nodules

大豆根瘤嘌呤合成酶的表征和定位

基本信息

批准号：
8904549
负责人：
Eric Triplett
金额：
$ 19.37万
依托单位：
University of Wisconsin-Madison
依托单位国家：
美国
项目类别：
Continuing Grant
财政年份：
1989
资助国家：
美国
起止时间：
1989-08-15 至 1992-07-31
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=8904549&HistoricalAwards=false
关键词：
Characterization Localization Purine Synthesis Enzymes

项目摘要

The pathway for purine biosynthesis has been detected in plastids which suggests that the genes for purine synthesis may be of prokaryotic or eukaryotic origin. Also, preliminary evidence suggests that there may be isozymes of the purine synthesis reactions. None of the enzymes of purine synthesis have been purified to homogeneity from a plant source. Soybean root nodules are an excellent model system for the study of purine synthesis in plants because these organs assimilate fixed nitrogen into the ureides, allantoin and allantoic acid, via purine synthesis. As a result, the purine synthesis pathway is highly expressed in nodules compared to other plant organs. These experiments address several important problems of purine synthesis in plants. Two enzymes of purine synthesis from nodules, glycinamide ribonucleotide transformylase and aminoimidazole ribonucleotide synthetase, will be purified and characterized. These enzymes catalyze the third and fifth committed steps, respectively, of purine synthesis. Using immunochemical and enzymatic assays, the distribution of these enzymes will be determined at the subcellular, cellular, and whole plant levels.%%% Little is known about purine synthesis in plants despite its importance in nitrogen metabolism. The production of ureides which are derived from purine synthesis is part of the process of supplying leaves and stems with nitrogen source they require. These studies will characterize two of the enzymes of the purine biosynthesis pathway as well as examine the expression and location of the genes responsible for purine synthesis. This research will provide a better understanding of nitrogen nutrition in plants.***//

嘌呤生物合成途径已在质体中检测到，这表明嘌呤合成基因可能是原核或真核起源的。此外，初步证据表明可能存在嘌呤合成反应的同工酶。尚未从植物来源中纯化出同质的嘌呤合成酶。大豆根瘤是研究植物嘌呤合成的绝佳模型系统，因为这些器官通过嘌呤合成将固定氮同化为酰脲、尿囊素和尿囊酸。因此，与其他植物器官相比，嘌呤合成途径在根瘤中高度表达。这些实验解决了植物中嘌呤合成的几个重要问题。将纯化和表征从根瘤合成嘌呤的两种酶：甘氨酰胺核糖核苷酸转化酶和氨基咪唑核糖核苷酸合成酶。这些酶分别催化嘌呤合成的第三和第五关键步骤。使用免疫化学和酶测定，将确定这些酶在亚细胞、细胞和整个植物水平上的分布。%%% 尽管嘌呤在氮代谢中很重要，但人们对植物中的嘌呤合成知之甚少。来自嘌呤合成的脲化物的生产是为叶和茎提供所需氮源的过程的一部分。这些研究将表征嘌呤生物合成途径中的两种酶，并检查负责嘌呤合成的基因的表达和位置。这项研究将有助于更好地了解植物中的氮营养。***//