Glutaredoxin (EC 1.15–1.21) is known as an oxidoreductase that protects cysteine residues within proteins against oxidative stress. Glutaredoxin catalyzes an electron transfer reaction that donates an electron to substrate proteins in the reducing system composed of glutaredoxin, glutathione, glutathione reductase, and nicotinamide-adenine dinucleotide phosphate (reduced form). 3-mercaptopyruvate sulfurtransferase (EC 2.8.1.2) is a cysteine enzyme that catalyzes transsulfuration, and glutaredoxin activates 3-mercaptopyruvate sulfurtransferase in the reducing system. Interestingly, even when glutathione or glutathione reductase was absent, 3-mercaptopyruvate sulfurtransferase activity increased, probably because reduced glutaredoxin was partly present and able to activate 3-mercaptopyruvate sulfurtransferase until depletion. A study using mutant Escherichia coli glutaredoxin1 (Cys¹⁴ is the binding site of glutathione and was replaced with a Ser residue) confirmed these results. Some inconsistency was noted, and glutaredoxin with higher redox potential than either 3-mercaptopyruvate sulfurtransferase or glutathione reduced 3-mercaptopyruvate sulfurtransferase. However, electron-transfer enzymatically proceeded from glutaredoxin to 3-mercaptopyruvate sulfurtransferase.

中文翻译：

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Glutaredoxin还原系统激活3-巯基丙酮酸硫转移酶。

谷胱甘肽毒素（EC 1.15–1.21）是一种氧化还原酶，可保护蛋白质中的半胱氨酸残基免受氧化应激。谷胱甘肽毒素催化电子转移反应，该电子转移反应将电子提供给底物蛋白质，该还原系统由谷胱甘肽毒素，谷胱甘肽，谷胱甘肽还原酶和烟酰胺-腺嘌呤二核苷酸磷酸酯（还原形式）组成。3-巯基丙酮酸硫转移酶（EC 2.8.1.2）是一种半胱氨酸酶，可催化转硫反应，而戊二酸在还原系统中激活3-巯基丙酮酸硫转移酶。有趣的是，即使不存在谷胱甘肽或谷胱甘肽还原酶，3-巯基丙酮酸硫转移酶活性也会增加，这可能是因为部分存在还原型谷胱甘肽毒素并能够激活3-巯基丙酮酸硫转移酶直至耗尽。使用突变体的研究大肠杆菌glutaredoxin1（Cys ¹⁴是谷胱甘肽的结合位点，并被Ser残基取代）证实了这些结果。注意到一些不一致，并且具有比3-巯基丙酮酸硫转移酶或谷胱甘肽更高的氧化还原电势的戊二醛还原3-巯基丙酮酸硫转移酶。但是，电子转移酶从谷氨酰氧转移到3-巯基丙酮酸硫转移酶。