Sheikh Hosseini Mehrnaz, Moosavi-Nejad Zahra, Rezaei Sadrabadi Fatemeh, Hosano Hamid
Department of Biotechnology, Faculty of Biological Sciences, Alzahra University, Tehran 1993893973, Iran.
Biomaterials Department, Institute of Industrial Nanomaterials, Kumamoto University, Kumamoto 860-8555, Japan.
Int J Mol Sci. 2025 Apr 27;26(9):4149. doi: 10.3390/ijms26094149.
Keratin-made biomaterials, including feathers, are considered a protein-rich bioresource due to their intrinsic properties, including biocompatibility, biodegradability, mechanical resistance, and biological abundance. Beta-keratin exists as an insoluble stringy protein due to the high presence of disulfide cross-links, and as a result, it is mechanically stable and resistant to enzymatic digestion. Because of this, it is not easily decomposed, and this has made the application of feathers difficult. In this study, after dissolving feathers in NaOH, sodium sulfide, and 2-Mercaptoethanol (2-ME), the relative molecular mass of beta-keratin was calculated. Thin-layer chromatography was also used to display proteins with lower molecular weights. The antioxidant activities of the samples were evaluated by Fe-chelating and free radical scavenging tests with 2,2-diphenyl-1-picrylhydrazyl (DPPH). To investigate the effect of blocking thiol groups on the antioxidant activity of dissolved keratin, iodoacetamide and HO were used. According to the three methods-(A) sodium hydroxide, (B) sodium sulfide, and (C) urea and 2-ME-used to extract and dissolve the feathers, method C caused the least change in the chemical structure of keratin molecules. Method A destroyed the primary structure of keratin and drastically reduced its molecular mass, but method B caused a drastic increase in the molecular mass from 9.6 kDa to higher masses, due to intermolecular bonds. For the keratin molecules dissolved by method C, the Fe-chelating activity was 93.18% and free radical scavenging was 77.45%. Blocking the thiol group with iodoacetamide initially reduced the free radical scavenging activity with DPPH by 42%, but blocking it with HO did not affect this activity. Also, blocking of the thiol group did not initially affect Fe-chelating activity and free radical scavenging activity. After a kinetic study of the activities, an interesting observation was that both blocking agents had negative effects on radical scavenging activity, but had positive effects on Fe-chelating activity. This indicates the complexity of the role of disulfide bonds in keratin's antioxidant behavior types. According to the observed antioxidant activities, it can be expected that beta-keratin extracted from chicken feathers is a suitable candidate for application in industrial, pharmaceutical, and health applications.
包括羽毛在内的角蛋白基生物材料，因其具有生物相容性、生物降解性、机械抗性和生物丰富性等固有特性，被视为富含蛋白质的生物资源。由于二硫键含量高，β-角蛋白以不溶性丝状蛋白质形式存在，因此它在机械性能上稳定且耐酶解。正因为如此，它不易分解，这使得羽毛的应用变得困难。在本研究中，将羽毛溶解于氢氧化钠、硫化钠和2-巯基乙醇（2-ME）中后，计算了β-角蛋白的相对分子质量。还使用薄层色谱法展示了较低分子量的蛋白质。通过用2,2-二苯基-1-苦基肼（DPPH）进行铁螯合和自由基清除试验，评估了样品的抗氧化活性。为了研究封闭巯基对溶解角蛋白抗氧化活性的影响，使用了碘乙酰胺和HO。根据用于提取和溶解羽毛的三种方法——（A）氢氧化钠、（B）硫化钠、（C）尿素和2-ME，方法C对角蛋白分子化学结构的改变最小。方法A破坏了角蛋白的一级结构并大幅降低了其分子量，但方法B由于分子间键合导致分子量从9.6 kDa急剧增加到更高值。对于用方法C溶解的角蛋白分子，铁螯合活性为93.18%，自由基清除率为77.45%。用碘乙酰胺封闭巯基最初使DPPH自由基清除活性降低了42%，但用HO封闭则不影响该活性。此外，封闭巯基最初并不影响铁螯合活性和自由基清除活性。在对这些活性进行动力学研究后，一个有趣的发现是，两种封闭剂对自由基清除活性都有负面影响，但对铁螯合活性有正面影响。这表明二硫键在角蛋白抗氧化行为类型中的作用具有复杂性。根据观察到的抗氧化活性，可以预期从鸡毛中提取的β-角蛋白是工业、制药和健康应用中的合适候选材料。
