ABSTRACT Pepsin enzyme from skipjack tuna was extracted for the production of kawakawa (Euthynnus affinis) fish protein hydrolysate. Using ultra-fractionation, Kawakawa protein hydrolysates were separated into four different fractions, including fractioned protein hydrolysate I (FPH I) (< 1 kDa), FPH-II (1–3 kDa), FPH-III (3–10 kDa), and FPH-IV (> 10 kDa). The antioxidant activity was assessed by 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging activity, inhibition of linoleic acid oxidation, reducing power tests, and chelating activity of metal ions. Results indicated that FPH II fraction peptides had higher antioxidant activity in comparison with the other fractions, followed by FPH I. Further, the fractions were evaluated for angiotensin converting enzyme (ACE) inhibition, and IC50 value ranged from 0.45 to 1.86 mg/ml with higher activity in FPH I (IC50 0.45). Finally, the amino acid profile of different fractions was analyzed. The fractions exhibited significant amounts of hydrophobic amino acids, which could perform as hydrogen donors, frustrate the free radicals, and inhibit the ACE. The recovered pepsin from the viscera was used to produce hydrolysates with good biological activities. Peptides lower than 3 KDa had antioxidant activity as positive controls and significant ACE activity. These are very important findings that could be used to conduct further research in a preclinical study of these peptides.

中文翻译：

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鲣鱼胃蛋白酶产生的川川 (Euthynnus affinis) 蛋白水解物的抗氧化和 ACE 抑制活性

摘要 从鲣鱼中提取胃蛋白酶用于生产川川 (Euthynnus affinis) 鱼蛋白水解物。使用超分馏，川川蛋白水解物被分成四个不同的部分，包括分馏蛋白水解物 I (FPH I) (< 1 kDa)、FPH-II (1-3 kDa)、FPH-III (3-10 kDa)、和 FPH-IV (> 10 kDa)。抗氧化活性通过2,2-二苯基-1-苦基肼(DPPH)自由基清除活性、亚油酸氧化抑制、还原能力测试和金属离子螯合活性来评估。结果表明，FPH II 级分肽与其他级分相比具有更高的抗氧化活性，其次是 FPH I。此外，评估了这些级分的血管紧张素转化酶 (ACE) 抑制作用，IC50 值范围为 0.45 至 1。86 mg/ml 在 FPH I 中具有更高的活性 (IC50 0.45)。最后，分析了不同级分的氨基酸谱。这些馏分显示出大量的疏水性氨基酸，它们可以作为氢供体、抑制自由基并抑制 ACE。从内脏中回收的胃蛋白酶用于生产具有良好生物活性的水解物。低于 3 KDa 的肽具有作为阳性对照的抗氧化活性和显着的 ACE 活性。这些是非常重要的发现，可用于在这些肽的临床前研究中进行进一步研究。并抑制ACE。从内脏中回收的胃蛋白酶用于生产具有良好生物活性的水解物。低于 3 KDa 的肽具有作为阳性对照的抗氧化活性和显着的 ACE 活性。这些是非常重要的发现，可用于在这些肽的临床前研究中进行进一步研究。并抑制ACE。从内脏中回收的胃蛋白酶用于生产具有良好生物活性的水解物。低于 3 KDa 的肽具有作为阳性对照的抗氧化活性和显着的 ACE 活性。这些是非常重要的发现，可用于在这些肽的临床前研究中进行进一步研究。