Isolation of Mitochondria from Leaf Tissue of Panicum miliaceum, a NAD-Malic Enzyme Type C(4) Plant.
Isolation of Mitochondria from Leaf Tissue of Panicum miliaceum, a NAD-Malic Enzyme Type C(4) Plant.
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从 Panicum miliaceum（C 型 NAD-苹果酸酶 C(4) 植物）叶组织中分离线粒体。
DOI：
10.1104/pp.71.1.24
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发表时间：
1983
期刊：
影响因子：
7.4
通讯作者：
G. Edwards
中科院分区：
文献类型：
--
作者：
P. Gardeström;G. Edwards
开发了一种机械分离程序来研究黍（一种 NAD-苹果酸酶 C(4) 植物）叶肉和束鞘组织中线粒体的呼吸特性。通过差别机械处理从幼叶中获得叶肉部分和束鞘部分。根据核酮糖二磷酸羧化酶活性和磷酸烯醇丙酮酸羧化酶活性的交叉污染分析，两个级分的纯度约为80％。通过差速离心和Percoll密度梯度离心从两个级分中分离线粒体。两种制剂中线粒体相对于叶绿体材料的富集约为 75 倍。两种类型的线粒体都通过呼吸控制氧化 NADH 和琥珀酸。叶肉线粒体中的苹果酸氧化对 KCN 敏感，表现出良好的呼吸控制作用。在束鞘线粒体中，苹果酸氧化对 KCN 基本上不敏感，并且没有表现出呼吸控制。水杨基异羟肟酸强烈抑制氧化，表明替代氧化酶参与其中。这种类型的 C(4) 物种的束鞘线粒体通过苹果酸脱羧来促进 C(4) 光合作用。与非偶联的替代途径相关的苹果酸氧化可能允许脱羧进行，而不受通过细胞色素链的偶联电子流可能发生的限制。
A mechanical isolation procedure was developed to study the respiratory properties of mitochondria from the mesophyll and bundle sheath tissue of Panicum miliaceum, a NAD-malic enzyme C(4) plant. A mesophyll fraction and a bundle sheath fraction were obtained from young leaves by differential mechanical treatment. The purity of both fractions was about 80%, based on analysis of the cross-contamination of ribulose bisphosphate carboxylase activity and phosphoenolpyruvate carboxylase activity.Mitochondria were isolated from the two fractions by differential centrifugation and Percoll density gradient centrifugation. The enrichment of mitochondria relative to chloroplast material was about 75-fold in both preparations.Both types of mitochondria oxidized NADH and succinate with respiratory control. Malate oxidation in mesophyll mitochondria was sensitive to KCN and showed good respiratory control. In bundle sheath mitochondria, malate oxidation was largely insensitive to KCN and showed no respiratory control. The oxidation was strongly inhibited by salicylhydroxamic acid, showing that the alternative oxidase was involved. The bundle sheath mitochondria of this type of C(4) species contribute to C(4) photosynthesis through decarboxylation of malate. Malate oxidation linked to an uncoupled, alternative pathway may allow decarboxylation to proceed without the restraints which might occur via coupled electron flow through the cytochrome chain.