College of Standardization, China Jiliang University, Hangzhou 310018, China.
Institute of Food Science, Zhejiang Academy of Agricultural Science, Hangzhou 310021, China.
Int J Biol Macromol. 2019 Apr 1;126:1186-1191. doi: 10.1016/j.ijbiomac.2019.01.017. Epub 2019 Jan 4.
β-lactoglobulin (β-lg), the predominant protein in bovine whey, was chemically modified by (-)-epigallocatechin-3-gallate (EGCG) to develop a biomacromolecule with antioxidant activity. The EGCG-modified β-lg was characterized by SDS-PAGE, MALDI-TOF MS and intrinsic fluorescence spectroscopy. The antioxidant properties of EGCG-modified β-lg was assessed using DPPH radical scavenging activity, iron chelating ability, and inhibition of Cu-induced LDL oxidation. SDS-PAGE and MALDI-TOF MS results indicated the dimerization of β-lg after EGCG modification. Intrinsic fluorescence spectra suggested that EGCG modification caused an alteration in the conformational structure of β-lg. The results demonstrated that EGCG-modified β-lg possessed great antioxidant potential in terms of scavenging DPPH radical and chelating ferrous ion. Furthermore, the EGCG-modified β-lg showed a protective effect against LDL peroxidation. The results indicate that EGCG-modified β-lg could provide significant health benefits as an antioxidant.
β-乳球蛋白（β-lg）是牛乳中的主要蛋白质，通过（-）-表没食子儿茶素-3-没食子酸酯（EGCG）化学修饰，开发出具有抗氧化活性的生物大分子。通过 SDS-PAGE、MALDI-TOF MS 和内源荧光光谱对 EGCG 修饰的β-lg 进行了表征。通过 DPPH 自由基清除活性、铁螯合能力和抑制 Cu 诱导的 LDL 氧化来评估 EGCG 修饰的β-lg 的抗氧化性能。SDS-PAGE 和 MALDI-TOF MS 结果表明，EGCG 修饰后β-lg 发生了二聚化。内源荧光光谱表明，EGCG 修饰导致β-lg 构象结构发生变化。结果表明，EGCG 修饰的β-lg 在清除 DPPH 自由基和螯合亚铁离子方面具有巨大的抗氧化潜力。此外，EGCG 修饰的β-lg 对 LDL 过氧化具有保护作用。结果表明，EGCG 修饰的β-lg 作为抗氧化剂可能具有重要的健康益处。
