Tu Maolin, Liu Hanxiong, Zhang Ruyi, Chen Hui, Mao Fengjiao, Cheng Shuzhen, Lu Weihong, Du Ming
School of Food Science and Technology, National Engineering Research Center of Seafood , Dalian Polytechnic University , Dalian , Liaoning 116034 , People's Republic of China.
Department of Food Science and Engineering, School of Chemistry and Chemical Engineering , Harbin Institute of Technology , Harbin , Heilongjiang 150001 , People's Republic of China.
J Agric Food Chem. 2018 Apr 25;66(16):4139-4144. doi: 10.1021/acs.jafc.8b00732. Epub 2018 Apr 13.
Casein hydrolysates exert various biological activities, and the responsible functional peptides are being identified from them continuously. In this study, the tryptic casein hydrolysate was fractionated by an ultrafiltration membrane (3 kDa), and the peptides were identified by capillary electrophoresis-quadrupole-time-of-flight-tandem mass spectrometry. Meanwhile, in silico methods were used to analyze the toxicity, solubility, stability, and affinity between the peptides and angiotensin-I-converting enzyme (ACE). Finally, a new angiotensin-I-converting enzyme inhibitory (ACEI) peptide, EKVNELSK, derived from α-casein (fragment 35-42) was screened. The half maximal inhibitory concentration value of the peptide is 5.998 mM, which was determined by a high-performance liquid chromatography method. The Lineweaver-Burk plot indicated that this peptide is a mixed-type inhibitor against ACE. Moreover, Discovery Studio 2017 R2 software was adopted to perform molecular docking to propose the potential mechanisms underlying the ACEI activity of the peptide. These results indicated that EKVNELSK is a new ACEI peptide identified from casein hydrolysate.
酪蛋白水解物具有多种生物活性，并且其中起作用的功能肽正在不断被鉴定出来。在本研究中，用超滤膜（3 kDa）对胰蛋白酶水解酪蛋白进行分级分离，并用毛细管电泳-四极杆-飞行时间串联质谱法鉴定肽段。同时，采用计算机模拟方法分析肽段的毒性、溶解性、稳定性以及肽段与血管紧张素I转换酶（ACE）之间的亲和力。最后，筛选出一种源自α-酪蛋白（片段35-42）的新型血管紧张素I转换酶抑制（ACEI）肽EKVNELSK。通过高效液相色谱法测定该肽的半数最大抑制浓度值为5.998 mM。Lineweaver-Burk图表明该肽是一种针对ACE的混合型抑制剂。此外，采用Discovery Studio 2017 R2软件进行分子对接，以提出该肽ACEI活性的潜在机制。这些结果表明EKVNELSK是从酪蛋白水解物中鉴定出的一种新型ACEI肽。
