Corpas Francisco J, Sandalio Luisa M, Del Río Luis A, Trelease Richard N
Department of Botany, Arizona State University, Tempe, AZ 85287-1601, USA.
Departamento de Bioquímica, Biología Celular y Molecular de Plantas, Estación Experimental del Zaidín, Consejo Superior de Investigaciones Científicas, Apartado 419, E-18080 Granada, Spain.
New Phytol. 1998 Feb;138(2):307-314. doi: 10.1046/j.1469-8137.1998.00899.x.
The number and type of isoforms of superoxide dismutase (SOD) and their activities were compared in mitochondria and peroxisomes isolated from cotyledons of three different oilseed seedlings. Mitochondrial and peroxisomal isoforms of SOD could be distinguished in nondenaturing polyacrylamide gels by their differential sensitivities to KCN and/or H O . The type of SOD was not the same for each organelle in each of the three oilseed species. For example, a single Mn-SOD was found in cotton and cucumber mitochondria, whereas four CuZn-SODs were present in mitochondria from sunflower. At least one CuZn-SOD isoform was found in the peroxisomes of all three species. Cucumber peroxisomes contained both a CuZn-SOD and a Mn-SOD, cotton peroxisomes contained a single CuZn-SOD, whilst four separate CuZn-SODs, but no Mn-SOD were found in sunflower peroxisomes. Using antibodies against CuZn-SOD from watermelon peroxisomes or from chloroplasts of Equisetum, a single polypeptide of c. 16·5 kDa was detected on immunoblots of peroxisomal fractions from the three species. Post-embedment, electron-microscopic double immunogold-labelling showed that CuZn-SOD, with malate synthase used as marker enzyme of peroxisomes, was localized in the matrix of these organelles of all three species. These results suggest that CuZn-SOD is a characteristic matrix enzyme of peroxisomes in oilseed cotyledons.
比较了从三种不同油籽幼苗子叶中分离出的线粒体和过氧化物酶体中超氧化物歧化酶（SOD）同工型的数量、类型及其活性。在非变性聚丙烯酰胺凝胶中，SOD的线粒体和过氧化物酶体同工型可通过它们对KCN和/或H₂O₂的不同敏感性来区分。在这三种油籽物种的每一种中，每个细胞器的SOD类型都不相同。例如，在棉花和黄瓜的线粒体中发现了单一的锰超氧化物歧化酶（Mn-SOD），而在向日葵的线粒体中有四种铜锌超氧化物歧化酶（CuZn-SOD）。在所有三种物种的过氧化物酶体中都发现了至少一种CuZn-SOD同工型。黄瓜过氧化物酶体中同时含有CuZn-SOD和Mn-SOD，棉花过氧化物酶体中含有单一的CuZn-SOD，而在向日葵过氧化物酶体中发现了四种不同的CuZn-SOD，但没有Mn-SOD。使用针对西瓜过氧化物酶体或木贼叶绿体中CuZn-SOD的抗体，在这三种物种过氧化物酶体组分的免疫印迹上检测到一条约16.5 kDa的单一多肽。包埋后，电子显微镜双免疫金标记显示，以苹果酸合酶作为过氧化物酶体的标记酶，CuZn-SOD定位于所有三种物种这些细胞器的基质中。这些结果表明，CuZn-SOD是油籽幼苗子叶过氧化物酶体的一种特征性基质酶。
