Glutathione-S-transferase (GST) is a key enzyme in the phase-II detoxification process and is a biomarker of oxidative stress. In this study, we analyzed the molecular, biochemical, and antioxidant properties of GST alpha-4 from Hippocampus abdominalis (HaGSTA-4). Also, the spatial and temporal expression of HaGSTA-4 upon immune challenge with abiotic and biotic stimulants were evaluated. The HaGSTA-4 ORF encodes 223 amino acids with a molecular weight of 25.7 kDa, and an estimated isoelectric point (pI) of 8.47. It consists of the GST_C superfamily and thioredoxin-like superfamily domain. The phylogenetic tree revealed that HaGSTA-4 is evolutionarily conserved with its GST alpha class counterparts. From pairwise alignment, the highest values of identity (78.5%) and similarity (85.7%) were with Parambassis ranga GSTA-4. Protein rHaGSTA-4 exhibited the highest conjugation activity towards 1-chloro-2,4-dinitrobenzene (CDNB) at pH 7 and 20 °C. A disk diffusion assay showed that rHaGSTA-4 significantly protects cells from the stress of exposure to ROS inducers such as CuSO₄, CdCl₂, and ZnCl₂. Furthermore, overexpressed HaGSTA-4 defended cells against oxidative stress caused by H₂O₂; evidence of selenium-independent peroxidase activity. From qPCR, the tissue-specific expression profile demonstrates that HaGSTA-4 is most highly expressed in the kidney, followed by the intestine and stomach, among fourteen different tissues extracted from healthy seahorses. The mRNA expression profile of HaGSTA-4 upon immune challenge varied depending on the tissue and the time after challenge. Altogether, this study suggests that HaGSTA-4 may be involved in protection against oxidative stress, in immune defense regulation, and xenobiotic metabolism.

谷胱甘肽-S-转移酶（GST）是II期解毒过程中的关键酶，并且是氧化应激的生物标记。在这项研究中，我们分析的分子，生物化学，和抗氧化性能GSTα-4-从海马腹（HaGSTA-4 ）。同样，评估了用非生物和生物刺激剂免疫攻击后HaGSTA-4的时空表达。所述HaGSTA-4 ORF编码具有25.7 kDa的分子量223个的氨基酸，和估计等电点（P我的8.47）。它由GST_C超家族和类似硫氧还蛋白的超家族域组成。系统发育树显示HaGSTA-4与GST alpha类对应物在进化上是保守的。从成对比对，同一性（78.5％）和相似性（85.7％）的最高值与Parambassis ranga GSTA-4相同。rHaGSTA-4蛋白在pH 7和20°C下对1-氯-2,4-二硝基苯（CDNB）表现出最高的结合活性。磁盘扩散分析表明，rHaGSTA-4可以有效保护细胞免受暴露于ROS诱导剂（如CuSO ₄，CdCl ₂和ZnCl _2）的压力。此外，过表达的HaGSTA-4可以防御H ₂ O ₂引起的氧化应激; 不依赖硒的过氧化物酶活性的证据。根据qPCR，组织特异性表达谱表明，在从健康海马中提取的十四种不同组织中，HaGSTA-4在肾脏中的表达最高，其次是肠和胃。免疫攻击后HaGSTA-4的mRNA表达谱根据攻击后的组织和时间而变化。总之，这项研究表明，HaGSTA-4可能参与抗氧化应激的保护，免疫防御调节和异源生物代谢。