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METABOLISM OF AROMATIC COMPOUNDS

芳香族化合物的代谢

基本信息

批准号：
3267878
负责人：
ERIC E CONN
金额：
$ 12.28万
依托单位：
UNIVERSITY OF CALIFORNIA AT DAVIS
依托单位国家：
美国
项目类别：
财政年份：
1977
资助国家：
美国
起止时间：
1977-03-01 至 1990-06-30
项目状态：
已结题

项目摘要

We propose to continue our biochemical studies of the metabolism of several aromatic cyanogenic glycosides, natural products, which occur in cyanogenic plants. The studies are desgined to obtain fundamental biochemical information concerning the metabolism of natural products on the assumption that any principles established will be applicable to other such compounds. Plant natural products include many substances (alkaloids, coumarins, flavonoids, glucosinolates) which are of medicinal and toxicological interest. Aromatic cyanogenic glycosides are derived from L-tyrosine and L-phenylalanine by a biosynthetic sequence involving the corresponding N-hydroxyamino acid, aldoxime, nitrile and cyanoydrin. Two of the four steps are catalyzed by mixed-function oxygenases. The biosynthetic sequence catalyzed by sorghum microsomes is metabolically channeled so that intermediates produced in situ are used more effectively than the same intermediates added externally to the microsomes. We propose to see whether particules from other cyanogenic seedlings (vetch and flax) are similarly channeled. Because efforts to solubilize the several enzymes involved have not yielded a soluble, purified protein whose molecular weight (size) could be determined, we shall used the technique of radiation inactivation to measure the molecular weight of the enzyme(s) involved. Such information should indicate whether the several enzymes are separate catalytic entitles or whether they function as a multi-enzyme complex. Cyanogenic sorghum seedlings possess an effective biosynthetic system for producing tyrosine from starch. Since little is known about the enzymes involved or their regulation, we propose to study the shikimate pathway in such seedlings. In particular, we will examine the role of the chloroplast in this process, since this organelle is now recognized as a site of synthesis of amino acids in plants. Finally, the mechanism of putative dehydration reaction (aldoxime greater than nitrile + H2O) which appears to require NADPH will be studied.

我们建议继续进行几种代谢的生物化学研究，芳香族氰苷，天然产物，存在于氰植物这些研究旨在获得基本的生物化学关于天然产物代谢的信息，所确立的任何原则将适用于其他此类化合物. 植物天然产物包括许多物质（生物碱，香豆素、类黄酮、芥子油苷），它们具有药用价值，毒理学兴趣。芳族生氰糖苷衍生自 L-酪氨酸和L-苯丙氨酸的生物合成序列，相应的N-羟基氨基酸、醛肟、腈和氰醇。两四个步骤中的一个是由混合功能加氧酶催化的。的高粱微粒体催化的生物合成序列是代谢性的，使原位产生的中间体得到更有效的利用比外部添加到微粒体中的相同中间体更高。我们提出看看其他生氰幼苗（野豌豆和亚麻）的颗粒都是类似的渠道。因为溶解几种酶的努力所涉及的蛋白质还没有产生可溶的、纯化的蛋白质，为了确定重量（尺寸），我们将使用辐射技术。失活以测量所涉及的酶的分子量。这些信息应表明这几种酶是否是分开的催化酶或它们是否作为多酶复合物起作用。生氰高粱幼苗具有有效的生物合成系统，从淀粉中产生酪氨酸。由于对酶知之甚少，参与或其调节，我们建议研究莽草酸途径，这样的种子。特别是，我们将研究叶绿体的作用在这个过程中，由于这个细胞器现在被认为是一个网站，植物中氨基酸的合成。最后，假定的脱水反应（醛肟大于腈+ H2O），需要NADPH进行研究。