Reynetha D.S. Rawendra, Aisha, Chi-I Chang, Aulanni'am, Ho-Hsien Chen, Tzou-Chi Huang, Jue-Liang Hsu
In this study, soft-shelled turtle (Pelodiscus sinensis) egg white (SSTEW) proteins were digested by thermolysin and the resulting small peptides were further fractionated by reverse phase chromatography. Peptides with angiotensin I-converting enzyme inhibitory (ACEI) activity from these fractions were screened. A lysozyme-derived peptide, IW-11, from the fraction with the most effective ACEI was identified by liquid chromatography-tandem mass spectrometry (LC-MS/MS) and its purified form showed effective ACEI activity in vitro (IC50=4.39±0.31μM). The Lineweaver-Burk plots indicated that the inhibition towards ACE caused by this peptide is a competitive inhibition. The molecular docking study further revealed that the ACEI activity of IW-11 is mainly attributed to the formation of hydrogen bonds between the N-terminal residue of IW-11 and the S1 pocket (Ala354 and Tyr523) and the S2' region (His513 and His353) of ACE. Moreover, the digestion parameters were further optimized and the target peptide (82% purity) was readily obtained (15% yield) without any cumbersome purification procedure. Notably, lysozyme C is the most abundant protein in SSTEW, which implies that an efficient production of this ACEI peptide from SSTEW is promising. © 2013 Elsevier B.V.
Department of Biological Science and Technology, National Pingtung University of Science and Technology, Pingtung, Taiwan; Department of Food Science, National Pingtung University of Science and Technology, 91201 Pingtung, Taiwan; Department of Food Science, Faculty of Agricultural Technology, University of Brawijaya, Malang, Indonesia; Department of Chemistry, Faculty of Sciences, University of Brawijaya, Malang, Indonesia; Research Center for Austronesian Medicine and Agriculture, National Pingtung University of Science and Technology, Pingtung, Taiwan; Research Center for Tropic Agriculture, National Pingtung University of Science and Technology, Pingtung, Taiwan
