BACKGROUND Spirulina platensis (S. platensis) is recognized as one of the most nutritious foods containing a high protein content up to 70%. Meanwhile, the interest in using natural protein resource to develop bio-active peptides is steadily increasing. Therefore, this study released the bio-active peptides from S. platensis by enzymatic hydrolysis using pepsin (1:3000 U/g), and their amino acid sequences were determined by de novo sequencing. On this basis, the antioxidant activities of synthesized bio-active peptides were comprehensively evaluated by 2,2'-azinobis-3-ethylbenzothiazolin-6-sulfonic acid (ABTS) assay, 1,1-diphenyl-2-picryhydrazyl (DPPH) assay, and cell hemolysis assay induced by 2,2'-azobis-(2-amidino-propane) dihydrochloride (AAPH). RESULTS The degree of hydrolysis and recovery percentage of pepsin hydrolysis was 172 g kg^-1 and 825 g kg^-1, respectively, and peptides containing m/z and the relative intensity of FFEFF (P1, m/z 736.4, 80%), EYFDALA (P2, m/z 828.4, 18.5%) and VTAPAASVAL (P3, m/z 899.5, 17.3%) were purified and identified. Thereinto, P2 possessed an excellent radical scavenging activity than P1, P3 and Vitamin c (Vc), which was contributed by its high β-sheet conformation and specific amino acid compositions. Moreover, P2 significantly attenuated AAPH-induced oxidative hemolysis of erythrocytes and protected the erythrocytes, because it reduced the formation of malondialdehyde and increased the enzyme activities of superoxide dismutase, catalase and glutathione peroxidase in erythrocytes. CONCLUSION This study provided insights into the potential antioxidant function of the synthesized peptides originated from the bio-active peptides of S. platensis proteins, which would contribute to the development of natural antioxidant from new protein resources. This article is protected by copyright. All rights reserved.

中文翻译：

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螺旋藻分离蛋白生物活性肽的回收鉴定及其体外抗氧化应激性红细胞溶血作用

背景螺旋藻（S. platensis）被认为是最有营养的食物之一，蛋白质含量高达70%。同时，利用天然蛋白质资源开发生物活性肽的兴趣也在稳步增加。因此，本研究通过胃蛋白酶（1:3000 U/g）酶解法从扁柏中释放出生物活性肽，并通过de novo测序确定其氨基酸序列。在此基础上,通过2,2'-azinobis-3-ethylbenzothiazolin-6-sulfonic acid (ABTS)检测、1,1-diphenyl-2-picryhydrazyl (DPPH)检测综合评价合成的生物活性肽的抗氧化活性, 以及由 2,2'-偶氮双-(2-脒基-丙烷) 二盐酸盐 (AAPH) 诱导的细胞溶血试验。结果胃蛋白酶水解度和回收率分别为172 g kg^-1和825 g kg^-1，含m/z的肽段和FFEFF的相对强度(P1, m/z 736.4, 80% )、EYFDALA (P2, m/z 828.4, 18.5%) 和 VTAPAASVAL (P3, m/z 899.5, 17.3%) 被纯化和鉴定。其中，P2 比 P1、P3 和维生素 c (Vc) 具有优异的自由基清除活性，这是由于其高 β-折叠构象和特定的氨基酸组成。此外，P2显着减弱AAPH诱导的红细胞氧化溶血并保护红细胞，因为它减少了丙二醛的形成并增加了红细胞中超氧化物歧化酶、过氧化氢酶和谷胱甘肽过氧化物酶的酶活性。结论本研究提供了对源自S.platensis蛋白质生物活性肽的合成肽的潜在抗氧化功能的见解，这将有助于从新的蛋白质资源中开发天然抗氧化剂。本文受版权保护。版权所有。