ABSTRACT

In order to isolate antioxidant peptides from oats globulin hydrolyzed alcalase, an antioxidant peptide was isolated and purified using ultra-filtration and ion-exchange chromatography. Hydroxyl and 1,1-diphenyl-2-pycrylhydrazyl (DPPH) radical scavenging capacity was analyzed to evaluate the antioxidant activity of peptide. Five fractions were obtained after ultra-filtration, fraction with molecular weight >10KDa showed the strongest hydroxyl and DPPH radical scavenging ability of 58.38 ± 0.87% and 24.53 ± 0.53% (p < 0.05). Fraction C which was purified via ion-exchange chromatography, exhibited the maximum antioxidant activity (IC₅₀ of hydroxyl and DPPH radical scavenging ability was 1.83 ± 0.03 mg mL⁻¹ and 4.11 ± 0.07 mg mL⁻¹) among other fractions (p < 0.05). Subsequently, five antioxidant peptides were identified by electrospray ionization mass spectrometry (ESI-MS/MS), with the amino acid sequence of IRIPIL, FLKPMT, NSKNFPTL, LIGRPIIY, and FNDILRRGQLL, with a molecular weight of 723.50, 735.40, 919.48, 943.59, and 1343.76 Da, respectively.

摘要

为了从燕麦球蛋白水解的碱性蛋白酶中分离抗氧化剂肽，使用超滤和离子交换色谱法分离并纯化抗氧化剂肽。分析了羟基和1,1-二苯基-2-吡啶基肼基（DPPH）自由基清除能力，以评估肽的抗氧化活性。超滤后得到五个馏分，分子量> 10KDa的馏分显示出最强的羟基和DPPH自由基清除能力，分别为58.38±0.87％和24.53±0.53％（p <0.05）。通过离子交换色谱纯化的馏分C具有最大的抗氧化活性（羟基和DPPH自由基的IC ₅₀清除能力分别为1.83±0.03 mg mL ^-1和4.11±0.07 mg mL ^-1）和其他分数（p <0.05）。随后，通过电喷雾电离质谱（ESI-MS / MS）鉴定了5种抗氧化剂肽，其氨基酸序列为IRIPIL，FLKPMT，NSKNFPTL，LIGRPIIY和FNDILRRGQLL，分子量分别为723.50、735.40、919.48、943.59，和1343.76 Da。