Nitric oxide is known to be a messenger in animals and plants. Catalase may regulate the concentration of intracellular *NO. In this study, yeast Saccharomyces cerevisiae cells were treated with 1-20 mM S-nitrosoglutathione (GSNO), a nitric oxide donor, which decreased yeast survival in a concentration-dependent manner. In the wild-type strain (YPH250), 20 mM GSNO reduced survival by 32%. The strain defective in peroxisomal catalase behaved like the wild-type strain, while a mutant defective in cytosolic catalase showed 10% lower survival. Surprisingly, survival of the double catalase mutant was significantly higher than that of the other strains used. Incubation of yeast with GSNO increased the activities of both superoxide dismutase (SOD) and catalase. Pre-incubation with cycloheximide prevented the activation of catalase, but not SOD. The concentrations of oxidized glutathione increased in the wild-type strain, as well as in the mutants defective in peroxisomal catalase and an acatalasaemic strain; it failed to do this in the mutant defective in cytosolic catalase. The activity of aconitase was reduced after GSNO treatment in all strains studied, except for the mutant defective in peroxisomal catalase. The content of protein carbonyls and activities of glutathione reductase and S-nitrosoglutathione reductase were unchanged following GSNO treatment. The increase in catalase activity due to incubation with GSNO was not found in a strain defective in Yap1p, a master regulator of yeast adaptive response to oxidative stress. The obtained data demonstrate that exposure of yeast cells to the *NO-donor S-nitrosoglutathione induced mild oxidative/nitrosative stress and Yap1p may co-ordinate the up-regulation of antioxidant enzymes under these conditions.

中文翻译：

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过氧化氢酶修饰了酿酒酵母对S-亚硝基谷胱甘肽诱导的应激的反应。

一氧化氮是动植物的信使。过氧化氢酶可以调节细胞内* NO的浓度。在这项研究中，用1-20 mM S-亚硝基谷胱甘肽（GSNO）（一种一氧化氮供体）处理了酿酒酵母细胞，该酵母以浓度依赖的方式降低了酵母的存活率。在野生型菌株（YPH250）中，20 mM GSNO使存活率降低了32％。过氧化物酶体过氧化氢酶缺陷菌株的行为与野生型菌株相似，而胞质过氧化氢酶缺陷突变体的存活率降低了10％。出乎意料的是，双过氧化氢酶突变体的存活率显着高于所用其他菌株的存活率。用GSNO孵育酵母可提高超氧化物歧化酶（SOD）和过氧化氢酶的活性。与环己酰亚胺预孵育可防止过氧化氢酶的激活，但不能阻止SOD的激活。在野生型菌株中，以及在过氧化物酶体过氧化氢酶和无催化性菌株中有缺陷的突变体中，氧化型谷胱甘肽的浓度增加。它在胞质过氧化氢酶缺陷突变体中未能做到这一点。在所有研究的菌株中，GSNO处理后乌头酸酶的活性均降低，除了过氧化物酶体过氧化氢酶有缺陷的突变体。GSNO处理后，蛋白质羰基的含量以及谷胱甘肽还原酶和S-亚硝基谷胱甘肽还原酶的活性没有变化。在与Yap1p缺陷的菌株中未发现由于与GSNO孵育而引起的过氧化氢酶活性的增加，Yap1p是酵母对氧化应激的适应性调节的主要调节因子。