南极磷虾多肽的组成及其抗氧化与ACE抑制活性

Composition Analysis and Evaluation of the Antioxidative and ACE Inhibitory Activities of Polypeptides from Antarctic Krill

以冷冻南极磷虾为原料,经碱溶酸沉法与酶解法联用制备南极磷虾多肽,采用紫外-可见光谱、红外光谱、凝胶色谱和氨基酸分析解析了多肽的组成和结构,并重点评价了多肽的抗氧化活性和血管紧张素I转化酶(angiotensin-I converting enzyme,ACE)抑制活性。结果表明:采用碱溶酸沉法与碱性蛋白酶酶解法联用制备南极磷虾多肽,水解度和肽得率可达到(17.83±3.73)%和(57.20±0.24)%。南极磷虾多肽的紫外最大特征吸收波长在273.5 nm;多肽在3390.84、2917.66、1648.36、1547.59 cm-1和1402.21 cm-1处具有红外特征吸收峰;多肽的分子量主要在189 Da^6500 Da范围内(98.93%),其中,451 Da^1450 Da占比最高(41.00±0.05)%;多肽的氨基酸组成理想,符合联合国粮农组织/世界卫生组织规定的标准。南极磷虾多肽具有显著的还原能力和良好的清除DPPH·、ABTS+自由基、·OH的能力,自由基清除IC50值分别为5.65、0.17、4.46 mg/mL;此外,多肽还具有良好的ACE抑制活性,当多肽浓度为0.5 mg/mL时,ACE抑制率为(55.91±2.63)%。

In the present study,alkali solution acid precipitation method and enzymatic hydrolysis method were combined to prepare active polypeptides using frozen Antarctic krill(Euphausia superba)as the raw material.The composition and structure characteristics of the polypeptides were systematically analyzed using ultraviolet-visible spectroscopy,infrared spectrometry,gel chromatography and amino acid analyzer.In addition,the antioxidative and angiotensin-I converting enzyme(ACE)inhibitory activities of the E.superba polypeptides were evaluated.The results showed that using the preparation method of the present study,the protein hydrolysis degree and peptides yield could reach up to(17.83±3.73)%and(57.20±0.24)%,respectively.The maximum characteristic absorption wavelength of the E.superba polypeptides was 273.5 nm,while the infrared characteristic absorption peaks were at 3390.84,2917.66,1648.36,1547.59 cm-1 and 1402.21 cm-1.The molecular weights of the E.superba polypeptides were mainly distributed in the range of 189 Da-6500 Da(98.93%),of which the highest proportion was 451 Da-1450 Da(41.00±0.05)%.The amino acid compositions of the E.superba polypeptides were ideal and met the standards stipulated by FAO/WHO.E.superba polypeptides showed significant reducing power and excellent DPPH·,ABTS+·and·OH scavenging abilities.The IC50 value of these indices were 5.65,0.17,4.46 mg/mL,respectively.Moreover,E.superba polypeptides also possessed prominent ACE inhibitory activity and the ACE inhibition rate was(55.91±2.63)%at the polypeptides concentration of 0.5 mg/mL.