Yousr Marwa, Howell Nazlin
Faculty of Health and Medical Sciences, the University of Surrey, Guildford, Surrey GU2 7XH, UK.
Int J Mol Sci. 2015 Dec 7;16(12):29161-78. doi: 10.3390/ijms161226155.
Protein by-products from the extraction of lecithin from egg yolk can be converted into value-added products, such as bioactive hydrolysates and peptides that have potential health enhancing antioxidant, and antihypertensive properties. In this study, the antioxidant and angiotensin converting enzyme (ACE) inhibitory activities of peptides isolated and purified from egg yolk protein were investigated. Defatted egg yolk was hydrolyzed using pepsin and pancreatin and sequentially fractionated by ultrafiltration, followed by gel filtration to produce egg yolk gel filtration fractions (EYGF). Of these, two fractions, EYGF-23 and EYGF-33, effectively inhibited the peroxides and thiobarbituric acid reactive substance (TBARS) in an oxidizing linoleic acid model system. The antioxidant mechanism involved superoxide anion and hydroxyl radicals scavenging and ferrous chelation. The presence of hydrophobic amino acids such as tyrosine (Y) and tryptophan (W), in sequences identified by LC-MS as WYGPD (EYGF-23) and KLSDW (EYGF-33), contributed to the antioxidant activity and were not significantly different from the synthetic BHA antioxidant. A third fraction (EYGF-56) was also purified from egg yolk protein by gel filtration and exhibited high ACE inhibitory activity (69%) and IC50 value (3.35 mg/mL). The SDNRNQGY peptide (10 mg/mL) had ACE inhibitory activity, which was not significantly different from that of the positive control captopril (0.5 mg/mL). In addition, YPSPV in (EYGF-33) (10 mg/mL) had higher ACE inhibitory activity compared with captopril. These findings indicated a substantial potential for producing valuable peptides with antioxidant and ACE inhibitory activity from egg yolk.
从蛋黄中提取卵磷脂产生的蛋白质副产品可转化为高附加值产品，如具有潜在健康促进作用的抗氧化和抗高血压特性的生物活性水解产物和肽。在本研究中，对从蛋黄蛋白中分离纯化的肽的抗氧化和血管紧张素转换酶（ACE）抑制活性进行了研究。用胃蛋白酶和胰酶水解脱脂蛋黄，然后依次通过超滤分级，再进行凝胶过滤以产生蛋黄凝胶过滤级分（EYGF）。其中，两个级分EYGF - 23和EYGF - 33在氧化亚油酸模型系统中有效抑制过氧化物和硫代巴比妥酸反应性物质（TBARS）。抗氧化机制涉及超氧阴离子和羟基自由基清除以及亚铁螯合。在通过LC - MS鉴定为WYGPD（EYGF - 23）和KLSDW（EYGF - 33）的序列中，存在诸如酪氨酸（Y）和色氨酸（W）等疏水氨基酸，这有助于抗氧化活性，并且与合成抗氧化剂丁基羟基茴香醚（BHA）没有显著差异。第三个级分（EYGF - 56）也通过凝胶过滤从蛋黄蛋白中纯化出来，并表现出高ACE抑制活性（69%）和IC50值（3.35 mg/mL）。SDNRNQGY肽（10 mg/mL）具有ACE抑制活性，与阳性对照卡托普利（0.5 mg/mL）相比没有显著差异。此外，（EYGF - 33）中的YPSPV（10 mg/mL）与卡托普利相比具有更高的ACE抑制活性。这些发现表明从蛋黄中生产具有抗氧化和ACE抑制活性的有价值肽具有很大潜力。
