Laboratory of Biophysics, School of Biological Sciences, and Institute of Microbiology, Seoul National University, Seoul 08826, Republic of Korea.
Department of Food and Nutrition, Institute of Food and Nutrition Science, Eulji University, Seongnam 13135, Republic of Korea.
J Microbiol Biotechnol. 2021 Jan 28;31(1):79-91. doi: 10.4014/jmb.2010.10057.
γ-Glutamylcysteine synthetase (Gcs1) and glutathione reductase (Glr1) activity maintains minimal levels of cellular methylglyoxal in . In glutathione-depleted , we previously saw that NAD(H)-linked methylglyoxal oxidoreductase (Mgd1) and alcohol dehydrogenase (Adh1) are the most active methylglyoxal scavengers. With methylglyoxal accumulation, disruptants lacking or exhibit a poor redox state. However, there is little convincing evidence for a reciprocal relationship between methylglyoxal scavenger genes-disrupted mutants and changes in glutathione-(in)dependent redox regulation. Herein, we attempt to demonstrate a functional role for methylglyoxal scavengers, modeled on a triple disruptant (//), to link between antioxidative enzyme activities and their metabolites in glutathione-depleted conditions. Despite seeing elevated methylglyoxal in all of the disruptants, the result saw a decrease in pyruvate content in // which was not observed in double gene-disrupted strains such as / and /. Interestingly, // exhibited a significantly decrease in HO and superoxide which was also unobserved in / and /. The activities of the antioxidative enzymes erythroascorbate peroxidase and cytochrome c peroxidase were noticeably higher in // than in the other disruptants. Meanwhile, Glr1 activity severely diminished in //. Monitoring complementary gene transcripts between double gene-disrupted / and / supported the concept of an unbalanced redox state independent of the Glr1 activity for //. Our data demonstrate the reciprocal use of Eapx1 and Ccp1 in the absence of both methylglyoxal scavengers; that being pivotal for viability in non-filamentous budding yeast.
γ-谷氨酰半胱氨酸合成酶（Gcs1）和谷胱甘肽还原酶（Glr1）的活性将细胞内甲基乙二醛的水平维持在最低水平。在谷胱甘肽耗竭的情况下，我们之前曾观察到 NAD（H）连接的甲基乙二醛氧化还原酶（Mgd1）和醇脱氢酶（Adh1）是最活跃的甲基乙二醛清除剂。随着甲基乙二醛的积累，缺乏 或 的缺陷体表现出较差的氧化还原状态。然而，缺乏甲基乙二醛清除剂基因的缺陷突变体与谷胱甘肽（非）依赖性氧化还原调节变化之间存在相互关系的证据很少。在此，我们试图通过模拟三突变体（//）来证明甲基乙二醛清除剂的功能作用，将抗氧化酶活性与其在谷胱甘肽耗竭条件下的代谢物联系起来。尽管在所有缺陷体中都观察到了甲基乙二醛的升高，但结果显示 // 的丙酮酸含量降低，而在双基因缺陷株如 / 和 / 中则没有观察到这种情况。有趣的是，// 表现出明显降低的 HO 和超氧化物，这在 / 和 / 中也没有观察到。抗氧化酶血红素加氧酶和细胞色素 c 过氧化物酶的活性在 // 中明显高于其他缺陷体。同时，// 中的 Glr1 活性严重降低。对双基因缺陷株 / 和 / 之间互补基因转录物的监测支持了 // 中 Glr1 活性与不平衡氧化还原状态无关的概念。我们的数据表明，在缺乏两种甲基乙二醛清除剂的情况下，Eapx1 和 Ccp1 可以相互利用；这对于非丝状出芽酵母的生存至关重要。
