Glutathione reductase (GSHR) is a biologically important enzyme involved in the conversion of oxidized glutathione (GSSG) into its reduced form, reduced glutathione (GSH), with the catalytic activity of NADPH. Most animals and aquatic organisms, including fish, possess high levels of this enzyme system to neutralize oxidative stress in cells. The current study was conducted to broaden our knowledge of GSHR in fish by identifying a mitochondrial isoform of this enzyme (LhGSHRm) in redlip mullet, Liza haematocheila, and clarifying its structure and function. The complete open reading frame of LhGSHRm consists of 1527 base pairs, encoding 508 amino acids, with a predicted molecular weight of 55.43 kDa. Multiple sequence alignment revealed the conservation of important amino acids in this fish. Phylogenetic analysis demonstrated the closest evolutionary relationship between LhGSHRm and other fish GSHRm counterparts. In tissue distribution analysis, the highest mRNA expression of LhGSHRm was observed in the gill tissue under normal physiological conditions. Following pathogenic challenges, the LhGSHRm transcription level was upregulated in a time-dependent manner in the gill and liver tissues, which may modulate the immune reaction against pathogens. rLhGSHRm showed considerable glutathione reductase activity in an enzyme assay. Further, the biological activity of rLhGSHRm in balancing cellular oxidative stress was observed in both disk diffusion and DPPH assays. Collectively, these results support that LhGSHRm has profound effects on modulating the immune reaction in fish to sustain precise redox homeostasis.

谷胱甘肽还原酶 (GSHR) 是一种生物学上重要的酶，参与将氧化型谷胱甘肽 (GSSG) 转化为还原型谷胱甘肽 (GSH)，具有 NADPH 的催化活性。大多数动物和水生生物，包括鱼，都具有高水平的这种酶系统，可以中和细胞中的氧化应激。目前的研究旨在通过鉴定红唇鲻鱼Liza haematocheila中这种酶的线粒体同种型 ( Lh GSHRm)并阐明其结构和功能，从而拓宽我们对鱼类 GSHR 的了解。Lh的完整开放阅读框GSHRm 由 1527 个碱基对组成，编码 508 个氨基酸，预测分子量为 55.43 kDa。多序列比对揭示了这条鱼中重要氨基酸的保守性。系统发育分析表明Lh GSHRm 与其他鱼类 GSHRm 对应物之间的进化关系最密切。在组织分布分析中，在正常生理条件下的鳃组织中观察到Lh GSHRm的最高mRNA表达。在病原体攻击后，Lh GSHRm 转录水平在鳃和肝组织中以时间依赖性方式上调，这可能调节针对病原体的免疫反应。[R于LhGSHRm 在酶分析中显示出相当大的谷胱甘肽还原酶活性。此外，在圆盘扩散和 DPPH 测定中都观察到了 r Lh GSHRm 在平衡细胞氧化应激方面的生物活性。总的来说，这些结果支持Lh GSHRm 对调节鱼的免疫反应以维持精确的氧化还原稳态具有深远的影响。