Yeast (Saccharomyces cerevisiae) essential for respiration and viability 1 (Erv1; EC number 1.8.3.2), a member of the flavin adenine dinucleotide-dependent Erv1/ALR disulphide bond generating enzyme family, works together with Mia40 to catalyse protein import and oxidative folding in the mitochondrial intermembrane space. Erv1/ALR functions either as an oxidase or cytochrome c reductase by passing electrons from a thiol substrate to molecular oxygen (O2 ) or cytochrome c, respectively. However, the substrate specificity for oxygen and cytochrome c is not fully understood. In this study, the oxidase and cytochrome c reductase kinetics of yeast Erv1 were investigated in detail, under aerobic and anaerobic conditions, using stopped-flow absorption spectroscopy and oxygen consumption analysis. Using DTT as an electron donor, our results show that cytochrome c is ~ 7- to 15-fold more efficient than O2 as electron acceptors for yeast Erv1, and that O2 is a competitive inhibitor of Erv1 cytochrome c reductase activity. In addition, Mia40, the physiological thiol substrate of Erv1, was used as an electron donor for Erv1 in a detailed enzyme kinetic study. Different enzyme kinetic kcat and Km values were obtained with Mia40 compared to DTT, suggesting that Mia40 modulates Erv1 enzyme kinetics. Taken together, this study shows that Erv1 is a moderately active enzyme with the ability to use both O2 and cytochrome c as the electron acceptors, indicating that Erv1 contributes to mitochondrial hydrogen peroxide production. Our results also suggest that Mia40-Erv1 system may involve in regulation of the redox state of glutathione in the mitochondrial intermembrane space. ERV1: EC number 1.8.3.2.

中文翻译：

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Erv1 的动力学表征，Erv1 是酵母线粒体中蛋白质导入和折叠的关键成分。

酵母（酿酒酵母）对呼吸和活力至关重要 1（Erv1；EC 编号 1.8.3.2），黄素腺嘌呤二核苷酸依赖性 Erv1/ALR 二硫键生成酶家族的成员，与 Mia40 一起催化蛋白质导入和氧化折叠在线粒体膜间隙。Erv1/ALR 通过将电子从硫醇底物分别传递到分子氧 (O2) 或细胞色素 c 来发挥氧化酶或细胞色素 c 还原酶的作用。然而，氧和细胞色素 c 的底物特异性尚不完全清楚。在这项研究中，在有氧和厌氧条件下，使用停流吸收光谱和耗氧量分析详细研究了酵母 Erv1 的氧化酶和细胞色素 c 还原酶动力学。使用 DTT 作为电子供体，我们的结果表明，细胞色素 c 作为酵母 Erv1 的电子受体的效率比 O2 高约 7 到 15 倍，并且 O2 是 Erv1 细胞色素 c 还原酶活性的竞争性抑制剂。此外，在详细的酶动力学研究中，Erv1 的生理硫醇底物 Mia40 被用作 Erv1 的电子供体。与 DTT 相比，Mia40 获得了不同的酶动力学 kcat 和 Km 值，表明 Mia40 调节 Erv1 酶动力学。总之，这项研究表明 Erv1 是一种中等活性的酶，能够同时使用 O2 和细胞色素 c 作为电子受体，表明 Erv1 有助于线粒体过氧化氢的产生。我们的结果还表明 Mia40-Erv1 系统可能参与调节线粒体膜间隙中谷胱甘肽的氧化还原状态。ERV1：