title: Angiotensin I-converting enzyme inhibitor derived from cross-linked oyster protein.
abstract: Following cross-linking by microbial transglutaminase, modified oyster proteins were hydrolyzed to improve inhibitory activity against angiotensin-converting enzyme (ACE) inhibitory activity with the use of a single protease, or a combination of six proteases. The oyster hydrolysate with the lowest 50% ACE inhibitory concentration (IC50) of 0.40 mg/mL was obtained by two-step hydrolysis of the cross-linked oyster protein using Protamex and Neutrase. Five ACE inhibitory peptides were purified from the oyster hydrolysate using a multistep chromatographic procedure comprised of ion-exchange, size exclusion, and reversed-phase liquid chromatography. Their sequences were identified as TAY, VK, KY, FYN, and YA, using automated Edman degradation and mass spectrometry. These peptides were synthesized, and their IC50 values were measured to be 16.7, 29.0, 51.5, 68.2, and 93.9 μM, respectively. Toxicity of the peptides on the HepG2 cell line was not detected. The oyster hydrolysate also significantly decreased the systolic blood pressure of spontaneously hypertensive rats (SHR). The antihypertensive effect of the oyster hydrolysate on SHR was rapid and long-lasting, compared to commercially obtained sardine hydrolysate. These results suggest that the oyster hydrolysate could be a source of effective nutraceuticals against hypertension.
authors.affiliation: Department of Seafood Science and Technology/Institute of Marine Industry, Gyeongsang National University, Gyeongnam-do 650-160, Republic of Korea.
authors.forename: Cheng-Liang
authors.initials: CL
authors.lastname: Xie
authors.affiliation: Department of Seafood Science and Technology/Institute of Marine Industry, Gyeongsang National University, Gyeongnam-do 650-160, Republic of Korea.
authors.forename: Jin-Soo
authors.initials: JS
authors.lastname: Kim
authors.affiliation: Department of Pharmaceutical Engineering, College of Medical and Life Science, Silla University, Busan 617-736, Republic of Korea.
authors.forename: Jong-Myung
authors.initials: JM
authors.lastname: Ha
authors.affiliation: Department of Hygienic Chemistry, College of Pharmacy, Kyung Hee University, Seoul 130-701, Republic of Korea.
authors.forename: Se-Young
authors.initials: SY
authors.lastname: Choung
authors.affiliation: Department of Seafood Science and Technology/Institute of Marine Industry, Gyeongsang National University, Gyeongnam-do 650-160, Republic of Korea.
authors.forename: Yeung-Joon
authors.identifier: 0000-0002-5124-4991
authors.initials: YJ
authors.lastname: Choi
mesh_terms: D000806:Angiotensin-Converting Enzyme Inhibitors / Q000008:administration & dosage / Q000737:chemistry / Q000302:isolation & purification*; D000818:Animals; D001794:Blood Pressure / Q000187:drug effects; D056945:Hep G2 Cells; D006801:Humans; D006973:Hypertension / Q000188:drug therapy* / Q000473:pathology; D010125:Ostreidae / Q000201:enzymology; D010455:Peptides / Q000008:administration & dosage / Q000737:chemistry / Q000302:isolation & purification*; D007703:Peptidyl-Dipeptidase A / Q000378:metabolism*; D051381:Rats
chemical_list: D000806:Angiotensin-Converting Enzyme Inhibitors; D010455:Peptides; D007703:Peptidyl-Dipeptidase A