Established and Proposed Roles of Xanthine Oxidoreductase in Oxidative and Reductive Pathways in Plants
Established and Proposed Roles of Xanthine Oxidoreductase in Oxidative and Reductive Pathways in Plants
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DOI：
10.1007/978-3-319-10079-1_2
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发表时间：
2015
期刊：
影响因子：
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通讯作者：
E. Urarte;R. Esteban;J. F. Moran;F. Bittner
中科院分区：
文献类型：
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作者：
E. Urarte;R. Esteban;J. F. Moran;F. Bittner
黄嘌呤氧化还原酶（Xanthine oxidoreductase，XOR）是真核细胞中研究最多的参与氧消耗的酶之一。然而，由于其参与体内自由基的产生，主要通过产生超氧自由基而引起研究者的注意。在植物中，XOR是参与嘌呤降解的关键酶，其中它催化次黄嘌呤氧化为黄嘌呤和黄嘌呤氧化为尿酸。这两种反应都伴随着电子转移到NAD+，同时形成NADH或分子氧，导致形成超氧自由基。植物异或突变体和分离的异或蛋白质从不同的植物物种的表征提供的证据表明，该酶在植物生长，叶片衰老，果实大小，合成的氮储存化合物，和植物病原体的相互作用中起着重要的作用。此外，XOR进行氧化还原反应的能力，如NADH氧化酶，并产生活性氧和一氧化氮，连同可能的补充作用，在脱落酸合成引起了进一步关注的重要性，这种酶。基于这些建立和建议的功能，XOR被讨论为植物生物学和农业中感兴趣的不同过程的调节器。
Xanthine oxidoreductase (XOR) is among the most-intensively studied enzymes known to participate in the consumption of oxygen in eukaryotic cells. However, it attracted the attention of researchers due its participation in free radical production in vivo, mainly through the production of superoxide radicals. In plants, XOR is a key enzyme involved in purine degradation where it catalyzes the oxidation of hypoxanthine to xanthine and of xanthine to uric acid. Both reactions are accompanied by electron transfer to either NAD+with simultaneous formation of NADH or to molecular oxygen, which results in formation of superoxide radicals. Characterization of plant XOR mutants and isolated XOR proteins from various plant species provided evidence that the enzyme plays significant role in plant growth, leaf senescence, fruit size, synthesis of nitrogen storage compounds, and plant–pathogen interactions. Moreover, the ability of XOR to carry out redox reactions as NADH oxidase and to produce reactive oxygen species and nitric oxide, together with a possible complementary role in abscisic acid synthesis have raised further attention on the importance of this enzyme. Based on these established and proposed functions, XOR is discussed as regulator of different processes of interest in plant biology and agriculture.