This study reports the antioxidant property and molecular mechanism of a tryptophan-tagged peptide derived from a teleost fish Channa striatus of serine threonine-protein kinase (STPK). The peptide was tagged with tryptophan to enhance the antioxidant property of STPK and named as IW13. The antioxidant activity of IW13 peptide was investigated using in vitro methods such as DPPH, ABTS, superoxide anion radical scavenging and hydrogen peroxide scavenging assay. Furthermore, to investigate the toxicity and dose response of IW13 peptide on antioxidant defence in vitro, L6 myotubes were induced with generic oxidative stress due to exposure of hydrogen peroxide (H₂O₂). IW13 peptide exposure was found to be non-cytotoxic to L6 cells in the tested concentration (10, 20, 30, 40 and 50 μM). Also, the pre-treatment of IW13 peptide decreased the lipid peroxidation level and increased glutathione enzyme activity. IW13 peptide treatment upregulated the antioxidant enzyme genes: GPx (glutathione peroxidase), GST (glutathione S transferase) and GCS (glutamine cysteine synthase), in vitro in L6 myotubes and in vivo in zebrafish larvae against the H₂O₂-induced oxidative stress. The results demonstrated that IW13 renders protection against the H₂O₂-induced oxidative stress through a cellular antioxidant defence mechanism by upregulating the gene expression, thus enhancing the antioxidant activity in the cellular or organismal level. The findings exhibited that the tryptophan-tagged IW13 peptide from STPK of C. striatus could be a promising candidate for the treatment of oxidative stress–associated diseases.

这项研究报告了从硬骨鱼丝氨酸苏氨酸蛋白激酶（STPK）的硬骨鱼Chan纹中提取的色氨酸标记肽的抗氧化特性和分子机理。该肽用色氨酸标记以增强STPK的抗氧化性能，并命名为IW13。使用DPPH，ABTS，超氧阴离子自由基清除和过氧化氢清除测定等体外方法研究了IW13肽的抗氧化活性。此外，为了研究IW13肽对体外抗氧化剂防御的毒性和剂量反应，通过过氧化氢（H ₂ O _2）的暴露，以一般的氧化应激诱导了L6肌管。）。发现在测试浓度（10、20、30、40和50μM）下，IW13肽暴露对L6细胞无细胞毒性。同样，IW13肽的预处理降低了脂质过氧化水平并增加了谷胱甘肽酶活性。IW13肽治疗在L6肌管中体外和在斑马鱼幼虫体内针对H ₂ O ₂诱导的氧化应激上调了抗氧化酶基因：GPx（谷胱甘肽过氧化物酶），GST（谷胱甘肽S转移酶）和GCS（谷氨酰胺半胱氨酸合酶）。。结果表明，IW13具有针对H ₂ O _2的保护作用通过上调基因表达通过细胞抗氧化剂防御机制引起的氧化应激，从而在细胞或生物体水平上增强抗氧化剂活性。研究结果表明，来自条纹衣原体STPK的色氨酸标记的IW13肽可能是治疗氧化应激相关疾病的有前途的候选药物。