College of Food Science and Technology, South China University of Technology, Guangzhou 510640, China.
College of Food Science and Technology, South China University of Technology, Guangzhou 510640, China.
Food Chem. 2020 Mar 5;308:125701. doi: 10.1016/j.foodchem.2019.125701. Epub 2019 Oct 19.
In this study, we found that glutaminase from Bacillus amyloliquefaciens could increase antioxidant activities of Gln-Cys mixture, demonstrated by the higher superoxide anion and DPPH radical scavenging activities, Fe-chelating and reducing power. According to UPLC-Q-TOF-MS/MS results, we identified γ-[Glu]-Cys in Gln-Cys mixture in the presence of glutaminase. The yields of γ-Glu-Cys (GC) and γ-Glu-γ-Glu-Cys (GGC) were 40.92% and 22.79% respectively, under the established optimum conditions: pH 10, 37 °C, 3 h, 0.1 mol/l Gln: 0.1 mol/l Cys = 1:1, and glutaminase at 0.1% (m/v). The antioxidant properties of GC, GGC, glutathione and Gln-Cys mixture in the presence of glutaminase were further compared and we found GC exhibited the highest superoxide anion and DPPH radical scavenging activities, and Fe-chelating and reducing power. Therefore, glutaminase caused the increase of antioxidant activity of Gln-Cys mixture and might be attributed to GC which was synthesized by glutaminase via transpeptidation, and GC has the potential to be used in food and nutraceutical applications as an antioxidant peptide.
在这项研究中，我们发现解淀粉芽孢杆菌的谷氨酰胺酶可以提高 Gln-Cys 混合物的抗氧化活性，这表现在超氧阴离子和 DPPH 自由基清除活性、Fe 螯合能力和还原能力更高。根据 UPLC-Q-TOF-MS/MS 的结果，我们在有谷氨酰胺酶存在的情况下鉴定出 Gln-Cys 混合物中的γ-[Glu]-Cys。在最佳条件下（pH 值 10、37°C、3 小时、0.1mol/L Gln:0.1mol/L Cys=1:1，谷氨酰胺酶用量为 0.1%（m/v）），γ-Glu-Cys（GC）和γ-Glu-γ-Glu-Cys（GGC）的产率分别为 40.92%和 22.79%。进一步比较了 GC、GGC、谷胱甘肽和有谷氨酰胺酶存在的 Gln-Cys 混合物的抗氧化性能，发现 GC 具有最高的超氧阴离子和 DPPH 自由基清除活性、Fe 螯合能力和还原能力。因此，谷氨酰胺酶引起了 Gln-Cys 混合物抗氧化活性的增加，这可能归因于谷氨酰胺酶通过转肽作用合成的 GC，GC 有可能作为一种抗氧化肽应用于食品和营养保健品。
