Mano Jun'ichi, Ishibashi Asami, Muneuchi Hitoshi, Morita Chihiro, Sakai Hiroki, Biswas Md Sanaullah, Koeduka Takao, Kitajima Sakihito
Science Research Center, Organization for Research Initiatives, Yamaguchi University, Yoshida 1677-1, Yamaguchi, 753-8515, Japan.
Graduate School of Sciences and Technology for Innovation, Yamaguchi University, Yoshida 1677-1, Yamaguchi, 753-8515, Japan.
Planta. 2017 Feb;245(2):255-264. doi: 10.1007/s00425-016-2604-5. Epub 2016 Oct 7.
Acrolein is a lipid-derived highly reactive aldehyde, mediating oxidative signal and damage in plants. We found acrolein-scavenging glutathione transferase activity in plants and purified a low K isozyme from spinach. Various environmental stressors on plants cause the generation of acrolein, a highly toxic aldehyde produced from lipid peroxides, via the promotion of the formation of reactive oxygen species, which oxidize membrane lipids. In mammals, acrolein is scavenged by glutathione transferase (GST; EC 2.5.1.18) isozymes of Alpha, Pi, and Mu classes, but plants lack these GST classes. We detected the acrolein-scavenging GST activity in four species of plants, and purified an isozyme showing this activity from spinach (Spinacia oleracea L.) leaves. The isozyme (GST-Acr), obtained after an affinity chromatography and two ion exchange chromatography steps, showed the K value for acrolein 93 μM, the smallest value known for acrolein-detoxifying enzymes in plants. Peptide sequence homology search revealed that GST-Acr belongs to the GST Tau, a plant-specific class. The Arabidopsis thaliana GST Tau19, which has the closest sequence similar to spinach GST-Acr, also showed a high catalytic efficiency for acrolein. These results suggest that GST plays as a scavenger for acrolein in plants.
丙烯醛是一种源自脂质的高反应性醛类，在植物中介导氧化信号和损伤。我们在植物中发现了清除丙烯醛的谷胱甘肽转移酶活性，并从菠菜中纯化出一种低K值同工酶。植物受到的各种环境胁迫会通过促进活性氧的形成来引发脂质过氧化物产生高毒性醛类丙烯醛，活性氧会氧化膜脂。在哺乳动物中，丙烯醛由α、π和μ类谷胱甘肽转移酶（GST；EC 2.5.1.18）同工酶清除，但植物缺乏这些GST类别。我们在四种植物中检测到了清除丙烯醛的GST活性，并从菠菜（Spinacia oleracea L.）叶片中纯化出一种具有该活性的同工酶。经过亲和层析和两步离子交换层析后获得的同工酶（GST-Acr）对丙烯醛的K值为93μM，这是植物中已知的丙烯醛解毒酶的最小值。肽序列同源性搜索表明GST-Acr属于GST Tau类，这是植物特有的一类。与菠菜GST-Acr序列最相似的拟南芥GST Tau19对丙烯醛也表现出高催化效率。这些结果表明GST在植物中充当丙烯醛的清除剂。
