Variations in the subunit content and catalytic activity of the cytochrome c oxidase complex from different tissues and different cardiac compartments.
Variations in the subunit content and catalytic activity of the cytochrome c oxidase complex from different tissues and different cardiac compartments.
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不同组织和不同心脏室的细胞色素c氧化酶复合物的亚基含量和催化活性存在差异。
DOI：
10.1016/s0005-2736(97)00278-2
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发表时间：
1998
期刊：
影响因子：
--
通讯作者：
Avadhani,NG
中科院分区：
文献类型：
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作者：
Vijayasarathy,C;Biunno,I;Lenka,N;Yang,M;Basu,A;Hall,IP;Avadhani,NG
研究了大鼠肝、脑、肾和心脏线粒体以及牛心脏不同部位线粒体细胞色素c氧化酶（考克斯）的组成和活性，以了解已知的氧化能力和考克斯活性之间是否存在任何相关性。免疫印迹分析显示，与心脏、肾脏和大脑相比，肝脏线粒体中普遍表达的亚基IV和Vb的水平低约8-12倍。具有较高丰度的考克斯IV和Vb的心脏酶显示较低的周转数（495），而具有较低丰度的这些亚基的肝酶显示较高的周转数（750）。为支持免疫印迹结果，心脏和肾脏组织切片的免疫组织化学分析显示，与肝脏切片相比，考克斯Vb抗体染色强烈。考克斯Vb抗体染色某些肾小管区域比其他区域更强烈，表明亚单位水平的区域特异性变化。牛心脏房室表现出亚单位水平的变化，也不同的考克斯的动力学参数。右心房含有相对较多的Vb蛋白，而左心室含有较高水平的亚基VIa。与心房考克斯（Km 8 -15 μM）相比，两个心室的考克斯显示细胞色素c的Km（23-37 μM）较高。这些结果表明，组织特异性氧化能力/工作负荷和亚基组成的变化之间的相关性和相关的变化，在考克斯复合物的活性。更重要的是，我们的研究结果表明，基于组织内细胞类型的氧化负荷的变化。
The composition and activity of cytochrome c oxidase (COX) was studied in mitochondria from rat liver, brain, kidney and heart and also in different compartments of the bovine heart to see whether any correlation exists between known oxidative capacity and COX activity. Immunoblot analysis showed that the levels of ubiquitously expressed subunits IV and Vb are about 8–12-fold lower in liver mitochondria as compared to the heart, kidney and brain. The heart enzyme with higher abundance of COX IV and Vb showed lower turnover number (495) while the liver enzyme with lower abundance of these subunits exhibited higher turnover number of 750. In support of the immunoblot results, immunohistochemical analysis of heart and kidney tissue sections showed an intense staining with the COX Vb antibody as compared to the liver sections. COX Vb antibody stained certain tubular regions of the kidney more intensely than the other regions suggesting region specific variation in the subunit level. Bovine heart compartments showed variation in subunit levels and also differed in the kinetic parameters of COX. The right atrium contained relatively more Vb protein, while the left ventricle contained higher level of subunit VIa. COX from both the ventricles showed high Kmfor cytochrome c (23–37 μM) as compared to the atrial COX (Km8–15 μM). These results suggest a correlation between tissue specific oxidative capacity/work load and changes in subunit composition and associated changes in the activity of COX complex. More important, our results suggest variations based on the oxidative load of cell types within a tissue.