Department of Biology, Howard University, Washington, DC, USA.
St. Jude Children's Research Hospital, Memphis, Tennessee, USA.
Free Radic Res. 2021 Jun;55(6):619-624. doi: 10.1080/10715762.2021.1979228.
The nematode has a contingent of five genes, one of the largest among aerobic organisms. Earlier studies revealed each of the five genes is capable of making perfectly active SOD proteins in heterologous expression systems therefore none appears to be a pseudogene. Yet deletion of the entire contingent of genes fails to impose any effect on the survival of except these animals appear more sensitive to extraneously applied oxidative stress conditions. We asked how many of the five genes are actually making active SOD enzymes in through the usage of in-gel SOD activity analysis and by using KCN as a selective inhibitor against Cu-ZnSOD enzyme(s). Here we provide evidence that out of the five SOD proteins only the mitochondrial SOD is active in the water-soluble fraction of extracts albeit at an apparently much lower activity than the multiple active SODs in and . We had no opportunity to test the activity of Sod-4a isoform which is possibly a membrane-bound form of SOD. The mutant analysis further confirmed that among the two mitochondrial SOD proteins, SOD-2 is the only naturally active SOD in .
线虫拥有五组基因，是需氧生物中基因数量最多的物种之一。早期的研究表明，这五组基因中的每一组都能在异源表达系统中产生完全活性的 SOD 蛋白，因此没有一组基因是假基因。然而，删除整个基因簇对线虫的存活没有任何影响，只是这些动物似乎对外部施加的氧化应激条件更敏感。我们想知道在线虫中，有多少个基因实际上在产生有活性的 SOD 酶，为此我们使用凝胶内 SOD 活性分析，并使用 KCN 作为铜锌 SOD 酶的选择性抑制剂。在这里，我们提供的证据表明，在五组 SOD 蛋白中，只有线粒体 SOD 在线虫水溶性部分中具有活性，尽管其活性明显低于 和 中的多个活性 SOD。我们没有机会测试 Sod-4a 同工酶的活性，它可能是 SOD 的一种膜结合形式。突变分析进一步证实，在线虫中，两种线粒体 SOD 蛋白中，SOD-2 是唯一具有天然活性的 SOD。
