Regulation and functions of polyphenol oxidases (PPOs) in the moss Physcomitrella

苔藓立碗藓中多酚氧化酶（PPO）的调控和功能

• 批准号: 35429487
• 负责人: Privatdozent Dr. Klaus von Schwartzenberg
• 金额: --
• 依托单位: Biozentrum Klein Flottbek und Botanischer Garten
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2006
• 资助国家: 德国
• 起止时间: 2005-12-31 至 2011-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/35429487?language=en
• 关键词: Regulation; functions; polyphenol; oxidases; PPOs

Polyphenol oxidases (PPOs) are almost ubiquitous enzymes, which oxidise polyphenols to highly reactive quinones. The exact biological function of PPOs is poorly understood. Our group identified the first bryophyte PPO gene in the moss Physcomitrella patens with several similarities but also differences to higher plant PPOs. Analysis of the derived amino acid sequence of the Physcomitrella PPO1 gene as well as enzymological studies revealed a strong membrane association. Transcription of PPO1 was shown to vary in the time course of a culture.The project uses the advantages of Physcomitrella as a model plant and focuses on: (a) functional studies on PPO using approaches of overexpression and gene knockout; (b) experiments on regulation of PPO on the levels of transcription and enzyme activity; (c) approaches to investigate enzyme properties such as subcellular localisation and substrate specificity. The chemical structure of the major phenolic compounds from Physcomitrella as potential PPO substrates will be identified. We assume that an elucidation of PPO functions in Physcomitrella as an early land plant can substantially help to understand the physiological and evolutionary role of this almost ubiquitous enzyme.

多酚氧化酶(PPO)是一种几乎普遍存在的酶，它能将多酚氧化成高活性的苯二酚。PPO的确切生物学功能还知之甚少。本课题组首次在青绿苔藓中发现了苔藓PPO基因，该基因与高等植物PPO有许多相似之处，但也有不同之处。对PPO1基因的氨基酸序列分析和酶学研究表明，PPO1基因具有很强的膜结合作用。PPO1的转录随着培养时间的推移而变化。该项目利用Physcomitella的优势作为模式植物，重点放在：(A)利用过表达和基因敲除的方法研究PPO的功能；(B)PPO对转录水平和酶活性的调节实验；(C)研究酶特性的方法，如亚细胞定位和底物专一性。作为潜在的PPO底物的Physcomitrella的主要酚类化合物的化学结构将被确定。我们认为，阐明多酚氧化酶作为早期陆地植物的功能有助于理解这种几乎无处不在的酶的生理和进化作用。