Fioravanti C F, Kim Y
Department of Biological Sciences, Bowling Green State University, OH 43403.
Mol Biochem Parasitol. 1988 Mar;28(2):129-34. doi: 10.1016/0166-6851(88)90060-6.
The occurrence of rhodoquinone as a mitochondrial membrane component was demonstrated in adult Hymenolepis diminuta. Chromatographic separation of pentane extracts, from lyophilized mitochondrial membranes, coupled with spectral analyses of separated material demonstrated the presence of rhodoquinone. The presence of ubiquinone was not apparent. Rhodoquinone content of membranes was about 1.2 micrograms (mg protein)-1. The rhodoquinone requirement of the H. diminuta electron transport system was demonstrated both in terms of the less active NADH oxidase and the physiologically required, NADH-dependent fumarate reductase employing lyophilized mitochondrial membranes as the source of activities. Pentane extraction of membranes virtually abolished the oxidase and fumarate reductase systems. Supplementation of pentane-treated membranes with H. diminuta rhodoquinone restored oxidase and fumarate reductase activities to levels simulating those of lyophilized membranes. Ubiquinone did not substitute for rhodoquinone. The rhodoquinone-reconstituted membranes displayed rotenone sensitivity. These findings represent the first direct demonstration of the rhodoquinone requirement of helminth electron transport-coupled oxidase and fumarate reductase.
在成年微小膜壳绦虫中证实了作为线粒体膜成分的泛醌的存在。对冻干线粒体膜的戊烷提取物进行色谱分离，并对分离出的物质进行光谱分析，证实了泛醌的存在。而辅酶Q的存在并不明显。膜中泛醌的含量约为1.2微克/（毫克蛋白质）-1。利用冻干线粒体膜作为活性来源，就活性较低的NADH氧化酶以及生理所需的、依赖NADH的延胡索酸还原酶而言，均证实了微小膜壳绦虫电子传递系统对泛醌的需求。膜的戊烷提取实际上消除了氧化酶和延胡索酸还原酶系统。用微小膜壳绦虫泛醌补充经戊烷处理的膜，可使氧化酶和延胡索酸还原酶活性恢复到模拟冻干膜的水平。辅酶Q不能替代泛醌。泛醌重构的膜表现出对鱼藤酮的敏感性。这些发现首次直接证明了蠕虫电子传递偶联氧化酶和延胡索酸还原酶对泛醌的需求。
