Department of Biotechnology, University of the Western Cape, Bellville, South Africa.
Plant Signal Behav. 2011 Jul;6(7):956-61. doi: 10.4161/psb.6.7.14879.
Ascorbate peroxidase is one of the major enzymes regulating the levels of H2O2 in plants and plays a crucial role in maintaining root nodule redox status. We used fully developed and mature nitrogen fixing root nodules from soybean plants to analyze the effect of exogenously applied nitric oxide, generated from the nitric oxide donor 2,2'-(hydroxynitrosohydrazono)bis-ethanimine, on the enzymatic activity of soybean root nodule ascorbate peroxidase. Nitric oxide caused an increase in the total enzymatic activity of ascorbate peroxidase. The nitric oxide-induced changes in ascorbate peroxidase enzymatic activity were coupled to altered nodule H2O2 content. Further analysis of ascorbate peroxidase enzymatic activity identified three ascorbate peroxidase isoforms for which augmented enzymatic activity occurred in response to nitric oxide. Our results demonstrate that nitric oxide regulates soybean root nodule ascorbate peroxidase activity. We propose a role of nitric oxide in regulating ascorbate-dependent redox status in soybean root nodule tissue.
抗坏血酸过氧化物酶是调节植物内 H2O2 水平的主要酶之一，在维持根瘤氧化还原状态方面起着至关重要的作用。我们使用来自大豆植物的完全发育和成熟的固氮根瘤来分析外源一氧化氮（由一氧化氮供体 2,2' -（羟亚硝基羟亚氨基）双乙脒产生）对大豆根瘤抗坏血酸过氧化物酶酶活性的影响。一氧化氮导致抗坏血酸过氧化物酶的总酶活性增加。一氧化氮诱导的抗坏血酸过氧化物酶酶活性变化与结瘤 H2O2 含量的改变有关。对抗坏血酸过氧化物酶酶活性的进一步分析确定了三种抗坏血酸过氧化物酶同工酶，它们的酶活性在一氧化氮的作用下增强。我们的结果表明，一氧化氮调节大豆根瘤的抗坏血酸过氧化物酶活性。我们提出一氧化氮在调节大豆根瘤组织中依赖抗坏血酸的氧化还原状态中的作用。
