Ji Wei, Zhang Chaohua, Ji Hongwu
College of Biological and Food Engineering, Guangzhou University of Education, Guangzhou, 510303, China.
College of Food Science and Technology, Guangdong Ocean University, Zhanjiang, 524088, China; Guangdong Provincial Key Laboratory of Aquatic Products Processing and Safety, Zhanjiang, 524088, China; Key Laboratory of Advanced Processing of Aquatic Products of Guangdong Higher Education Institution, Zhanjiang, 524088, China.
J Chromatogr B Analyt Technol Biomed Life Sci. 2017 Oct 1;1064:56-61. doi: 10.1016/j.jchromb.2017.09.001. Epub 2017 Sep 5.
Dipeptidyl peptidase IV (DPP-IV) played an important role in blood glucose regulation. Inhibition of DPP-IV may improve glycemic control in diabetics by preventing the rapid breakdown of incretin hormones and prolonging their physiological action. In this study, Antarctic krill (Euphausia superba) protein was hydrolyzed using animal proteolytic enzymes. The hydrolysate was purified sequentially by ultrafiltration, gel filtration chromatography and reversed phase high-performance liquid chromatography (RP-HPLC). DPP-IV inhibitory activity of the fractions achieved from Antarctic krill protein was determined by DPP-IV screening reagent kit. Two purified peptides were identified by Xevo G2-XS QTof mass spectrometer (QTOF-MS). One peptide purified was Ala-Pro (AP) with IC values of 0.0530mg/mL, the other Ile-Pro-Ala (IPA) with IC values of 0.0370mg/mL. They both exhibited strong DPP-IV inhibitory activity. The molecular docking analysis revealed that DPP-IV inhibition by AP and IPA was mainly due to formation of a strong interaction surface force with the 91-96 and 101-105 amino acids of the DPP-IV. Our results suggested that the protein hydrolysate from Antarctic krill can be considered as a promising natural source of DPP-IV inhibitory peptides in the management of diabetes.
二肽基肽酶IV（DPP-IV）在血糖调节中发挥着重要作用。抑制DPP-IV可通过防止肠促胰岛素激素的快速分解并延长其生理作用来改善糖尿病患者的血糖控制。在本研究中，使用动物蛋白水解酶对南极磷虾蛋白进行水解。水解产物依次通过超滤、凝胶过滤色谱和反相高效液相色谱（RP-HPLC）进行纯化。采用DPP-IV筛选试剂盒测定南极磷虾蛋白所得组分的DPP-IV抑制活性。通过Xevo G2-XS QTof质谱仪（QTOF-MS）鉴定出两种纯化肽。一种纯化肽为丙氨酸-脯氨酸（AP），IC值为0.0530mg/mL，另一种为异亮氨酸-脯氨酸-丙氨酸（IPA），IC值为0.0370mg/mL。它们均表现出较强的DPP-IV抑制活性。分子对接分析表明，AP和IPA对DPP-IV的抑制作用主要是由于与DPP-IV的91-96和101-105位氨基酸形成了强大的相互作用表面力。我们的结果表明，南极磷虾蛋白水解产物可被视为糖尿病管理中一种有前景的DPP-IV抑制肽天然来源。
