College of Food Science and Technology, Jilin University, Changchun, 130062, PR China.
College of Food Science and Technology, Jilin University, Changchun, 130062, PR China; National Engineering Research Center of Seafood, School of Food Science and Technology, Dalian Polytechnic University, Dalian 116034, PR China.
Food Res Int. 2018 Mar;105:836-844. doi: 10.1016/j.foodres.2017.12.022. Epub 2017 Dec 9.
The composition, structure, and proper positioning of amino acid in a peptide are closely related to its antioxidant activity. In this study, we purified antioxidant peptides from corn protein hydrolysates (CPH) and identified novel antioxidant peptides from fraction CPH2-III as Ala-Gly-Ile/Leu-Pro-Met (AGI/LPM; 487.62Da) and His-Ala-Ile/Leu-Gly-Ala (HAI/LGA; 467.53Da). AGLPM and HALGA exhibited better oxygen radical absorbance capacities than AGIPM and HAIGA did (P<0.05), as assessed using HepG2 cells with the cellular antioxidant activity assay (CAA) and electron spin resonance (ESR) spectroscopy. Finally, the secondary structure was determined using circular dichroism (CD). ESR showed that the AGLPM and HALGA peptides had the strongest abilities to scavenge hydroxyl radicals, by 79.41±1.41% and 75.16±2.26%, respectively. Thus, corn gluten meal could be used as a potential source of antioxidant peptides for food applications. Additionally, the amino acid Leu compared with Ile may be a critical factor contributing to strong antioxidant activity than the Ile in the peptide sequence (not C-terminus or N-terminus) and CD showed that the lower α-helix and random coil are the main causes.
氨基酸在肽中的组成、结构和正确定位与其抗氧化活性密切相关。在本研究中，我们从玉米蛋白水解物（CPH）中纯化了抗氧化肽，并从 CPH2-III 级分中鉴定出新型抗氧化肽为 Ala-Gly-Ile/Leu-Pro-Met（AGI/LPM；487.62Da）和 His-Ala-Ile/Leu-Gly-Ala（HAI/LGA；467.53Da）。AGI/LPM 和 HAI/LGA 的氧自由基吸收能力优于 AGIPM 和 HAIGA（P<0.05），这是通过 HepG2 细胞中的细胞抗氧化活性测定（CAA）和电子自旋共振（ESR）光谱评估的。最后，使用圆二色性（CD）确定二级结构。ESR 表明，AGLPM 和 HALGA 肽具有最强的清除羟基自由基的能力，分别为 79.41±1.41%和 75.16±2.26%。因此，玉米蛋白粉可用作食品应用中抗氧化肽的潜在来源。此外，与异亮氨酸相比，亮氨酸可能是导致肽序列（非 C 末端或 N 末端）中亮氨酸具有较强抗氧化活性的关键因素，CD 表明较低的α-螺旋和无规卷曲是主要原因。
