Zhao Yuanhui, Li Bafang, Dong Shiyuan, Liu Zunying, Zhao Xue, Wang Jingfeng, Zeng Mingyong
College of Food Science and Engineering, Ocean University of China, Qingdao, China.
Peptides. 2009 Jun;30(6):1028-33. doi: 10.1016/j.peptides.2009.03.002. Epub 2009 Mar 24.
Body wall protein from the sea cucumber (Acaudina molpadioidea) was hydrolyzed sequentially with bromelain and alcalase. The hydrolysate was fractionated into two ranges of molecular weight (PH-I, >2 kDa; PH-II, <2kDa) using an ultrafiltration membrane bioreactor system. The PH-II brought about a high angiotensin I-converting enzyme (ACE) inhibitory activity. An ACE inhibitory peptide was isolated from the PH-II, using the chromatographic methods including gel filtration, ion-exchange chromatography and reversed phase high-performance liquid chromatography. The purified ACE inhibitory peptide was a novel peptide, showing very low similarity to other ACE inhibitory peptide sequences, and was sequenced as MEGAQEAQGD. It was found that the inhibitory activity of the peptide was intensified by 3.5 times from IC(50) 15.9 to IC(50) 4.5 microM after incubation with gastrointestinal proteases. The ACE inhibitory peptide from A. molpadioidea showed a clear antihypertensive effect in spontaneously hypertensive rats (SHR), at a dosage of 3 microM/kg.
用菠萝蛋白酶和碱性蛋白酶依次水解海参（莫氏海参）的体壁蛋白。使用超滤膜生物反应器系统将水解产物按分子量范围分为两部分（PH-I，>2 kDa；PH-II，<2 kDa）。PH-II具有较高的血管紧张素I转换酶（ACE）抑制活性。采用凝胶过滤、离子交换色谱和反相高效液相色谱等色谱方法从PH-II中分离出一种ACE抑制肽。纯化后的ACE抑制肽是一种新型肽，与其他ACE抑制肽序列的相似性非常低，其序列为MEGAQEAQGD。研究发现，该肽与胃肠道蛋白酶孵育后，其抑制活性从IC(50) 15.9 μM增强到IC(50) 4.5 μM，增强了3.5倍。来自莫氏海参的ACE抑制肽在自发性高血压大鼠（SHR）中以3 μM/kg的剂量显示出明显的降压作用。
