Tang Ning, Liu Jiachen, Cheng Yongqiang
College of Food Science and Nutritional Engineering, China Agricultural University, Beijing Key Laboratory of Functional Food from Plant Resources, Beijing 100083, China.
College of Food Science and Nutritional Engineering, China Agricultural University, Beijing Key Laboratory of Functional Food from Plant Resources, Beijing 100083, China.
Food Chem. 2021 Sep 30;357:129750. doi: 10.1016/j.foodchem.2021.129750. Epub 2021 Apr 8.
Serum albumin as a zinc carrier binds 80% plasma zinc to facilitate zinc absorption. Epigallocatechin gallate (EGCG, green tea) is reported to bind to serum albumin to perform its biological functions in vivo. However, the available information on how zinc binding affects the binding of EGCG to proteins or how EGCG binding affects the binding of zinc to proteins are very limited. In the present study, the effects of zinc binding on the binding of EGCG to bovine serum albumin and myoglobin were investigated using isothermal titration calorimetry, fluorescence quenching and molecular docking. The obtained results suggested that binding of zinc to bovine serum albumin and myoglobin could increase the EGCG binding affinity of proteins as indicated by the thermodynamic parameters. In addition, the formation of protein/zinc complex shifted the EGCG binding site of proteins. For myoglobin, the electron transfer from EGCG to myoglobin was facilitated by zinc binding induced stronger EGCG binding to myoglobin. Such study provides very fundamental and useful knowledge for zinc and EGCG nutrition.
血清白蛋白作为锌载体可结合80%的血浆锌以促进锌吸收。据报道，表没食子儿茶素没食子酸酯（EGCG，绿茶）可与血清白蛋白结合，在体内发挥其生物学功能。然而，关于锌结合如何影响EGCG与蛋白质的结合，或EGCG结合如何影响锌与蛋白质的结合，现有信息非常有限。在本研究中，采用等温滴定量热法、荧光猝灭和分子对接，研究了锌结合对EGCG与牛血清白蛋白和肌红蛋白结合的影响。获得的结果表明，锌与牛血清白蛋白和肌红蛋白的结合可增加蛋白质对EGCG的结合亲和力，这由热力学参数表明。此外，蛋白质/锌复合物的形成改变了蛋白质的EGCG结合位点。对于肌红蛋白，锌结合诱导EGCG与肌红蛋白更强的结合，从而促进了EGCG向肌红蛋白的电子转移。此类研究为锌和EGCG营养提供了非常基础且有用的知识。
