{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,18]],"date-time":"2026-10-18T03:00:16Z","timestamp":1792292416275,"version":"4.4.0"},"reference-count":50,"publisher":"MDPI AG","issue":"3","license":[{"start":{"date-parts":[[2019,3,19]],"date-time":"2019-03-19T00:00:00Z","timestamp":1552953600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100004731","name":"Natural Science Foundation of Zhejiang Province","doi-asserted-by":"publisher","award":["LZ17D060001"],"award-info":[{"award-number":["LZ17D060001"]}],"id":[{"id":"10.13039\/501100004731","id-type":"DOI","asserted-by":"publisher"}]},{"name":"Ningbo International Cooperation Program","award":["2017D10019"],"award-info":[{"award-number":["2017D10019"]}]},{"DOI":"10.13039\/501100007928","name":"Ningbo Municipal Bureau of Science and Technology","doi-asserted-by":"publisher","award":["2016C10034"],"award-info":[{"award-number":["2016C10034"]}],"id":[{"id":"10.13039\/501100007928","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Marine Drugs"],"abstract":"<jats:p>Angiotensin I-converting enzyme (ACE) inhibitory peptides derived from seaweed represent a potential source of new antihypertensive. The aim of this study was to isolate and purify ACE inhibitory peptides (ACEIPs) from the protein hydrolysate of the marine macroalga Ulva intestinalis. U. intestinalis protein was hydrolyzed by five different proteases (trypsin, pepsin, papain, \u03b1-chymotrypsin, alcalase) to prepare peptides; compared with other hydrolysates, the trypsin hydrolysates exhibited the highest ACE inhibitory activity. The hydrolysis conditions were further optimized by response surface methodology (RSM), and the optimum conditions were as follows: pH 8.4, temperature 28.5 \u00b0C, enzyme\/protein ratio (E\/S) 4.0%, substrate concentration 15 mg\/mL, and enzymolysis time 5.0 h. After fractionation and purification by ultrafiltration, gel exclusion chromatography and reverse-phase high-performance liquid chromatography, two novel purified ACE inhibitors with IC50 values of 219.35 \u03bcM (0.183 mg\/mL) and 236.85 \u03bcM (0.179 mg\/mL) were obtained. The molecular mass and amino acid sequence of the ACE inhibitory peptides were identified as Phe-Gly-Met-Pro-Leu-Asp-Arg (FGMPLDR; MW 834.41 Da) and Met-Glu-Leu-Val-Leu-Arg (MELVLR; MW 759.43 Da) by ultra-performance liquid chromatography-tandem mass spectrometry. A molecular docking study revealed that the ACE inhibitory activities of the peptides were mainly attributable to the hydrogen bond and Zn(II) interactions between the peptides and ACE. The results of this study provide a theoretical basis for the high-valued application of U. intestinalis and the development of food-derived ACE inhibitory peptides.<\/jats:p>","DOI":"10.3390\/md17030179","type":"journal-article","created":{"date-parts":[[2019,3,19]],"date-time":"2019-03-19T12:12:25Z","timestamp":1552997545000},"page":"179","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":134,"title":["Preparation and Identification of ACE Inhibitory Peptides from the Marine Macroalga Ulva intestinalis"],"prefix":"10.3390","volume":"17","author":[{"given":"Siqi","family":"Sun","sequence":"first","affiliation":[{"name":"School of Marine Sciences, Ningbo University, Ningbo 315211, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Xiaoting","family":"Xu","sequence":"additional","affiliation":[{"name":"School of Marine Sciences, Ningbo University, Ningbo 315211, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Xue","family":"Sun","sequence":"additional","affiliation":[{"name":"School of Marine Sciences, Ningbo University, Ningbo 315211, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Xiaoqian","family":"Zhang","sequence":"additional","affiliation":[{"name":"School of Marine Sciences, Ningbo University, Ningbo 315211, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Xinping","family":"Chen","sequence":"additional","affiliation":[{"name":"Division of Allergy, Pulmonary, and Critical Care Medicine, Vanderbilt University Medical Center, Nashville, TN 37232, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Nianjun","family":"Xu","sequence":"additional","affiliation":[{"name":"School of Marine Sciences, Ningbo University, Ningbo 315211, China"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2019,3,19]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"302","DOI":"10.1016\/j.foodchem.2008.03.059","article-title":"Purification and identification of a ACE inhibitory peptide from oyster proteins hydrolysate and the antihypertensive effect of hydrolysate in spontaneously hypertensive rats","volume":"111","author":"Wang","year":"2008","journal-title":"Food Chem."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"37","DOI":"10.1016\/j.foodchem.2014.11.013","article-title":"Angiotensin-I converting enzyme inhibitory peptides from antihypertensive skate (Okamejei kenojei) skin gelatin hydrolysate in spontaneously hypertensive rats","volume":"174","author":"Ngo","year":"2015","journal-title":"Food Chem."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"2789","DOI":"10.1080\/10408398.2015.1068736","article-title":"Production of angiotensin I converting enzyme inhibitory (ACE-I) peptides during milk fermentation and their role in reducing hypertension","volume":"57","author":"Rai","year":"2017","journal-title":"Crit. Rev. Food Sci. Nutr."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"870","DOI":"10.1016\/j.foodchem.2009.05.080","article-title":"A HPLC-UV method for the determination of angiotensin I-converting enzyme (ACE) inhibitory activity","volume":"118","author":"Lahogue","year":"2010","journal-title":"Food Chem."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"23","DOI":"10.1016\/0014-2999(88)90629-2","article-title":"Differential effects of oral trandolapril and enalapril on rat tissue angiotensin-converting enzyme","volume":"147","author":"Chevillard","year":"1988","journal-title":"Eur. J. Pharmacol."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"980S","DOI":"10.1093\/jn\/134.4.980S","article-title":"Hypotensive Peptides from Milk Proteins","volume":"134","author":"FitzGerald","year":"2004","journal-title":"J. Nutr."},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"1277","DOI":"10.1016\/j.idairyj.2006.06.004","article-title":"Physiological, chemical and technological aspects of milk-protein-derived peptides with antihypertensive and ACE-inhibitory activity","volume":"16","author":"Otte","year":"2006","journal-title":"Int. Dairy J."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"196","DOI":"10.1016\/j.jff.2016.03.026","article-title":"Revalorisation of bovine collagen as a potential precursor of angiotensin I-converting enzyme (ACE) inhibitory peptides based on in silico and in vitro protein digestions","volume":"24","author":"Fu","year":"2016","journal-title":"J. Funct. Foods"},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"396","DOI":"10.1016\/j.foodchem.2013.10.053","article-title":"Novel angiotensin I-converting enzyme inhibitory peptides derived from edible mushroom Agaricus bisporus (J.E. Lange) Imbach identified by LC\u2013MS\/MS","volume":"148","author":"Lau","year":"2014","journal-title":"Food Chem."},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"1684","DOI":"10.1016\/j.jff.2013.07.013","article-title":"Angiotensin-I converting enzyme (ACE) inhibitory tripeptides from rice protein hydrolysate: Purification and characterization","volume":"5","author":"Chen","year":"2013","journal-title":"J. Funct. Foods"},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"743","DOI":"10.1016\/j.procbio.2008.02.019","article-title":"ACE-inhibitory peptides identified from the muscle protein hydrolysate of hard clam (Meretrix lusoria)","volume":"43","author":"Tsai","year":"2008","journal-title":"Process Biochem."},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"1829","DOI":"10.1007\/s00217-017-2886-2","article-title":"Purification and identification of a novel ACE inhibitory peptide from marine alga Gracilariopsis lemaneiformis protein hydrolysate","volume":"243","author":"Cao","year":"2017","journal-title":"Eur. Food Res. Technol."},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"508","DOI":"10.1016\/j.biotechadv.2011.05.017","article-title":"Health benefits of marine foods and ingredients","volume":"29","author":"Larsen","year":"2011","journal-title":"Biotechnol. Adv."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"6829","DOI":"10.1021\/jf201114d","article-title":"Heart Health Peptides from Macroalgae and Their Potential Use in Functional Foods","volume":"59","author":"Fitzgerald","year":"2011","journal-title":"J. Agric. Food Chem."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"267","DOI":"10.1016\/j.jnutbio.2003.11.004","article-title":"Antihypertensive effects of Undaria pinnatifida (wakame) peptide on blood pressure in spontaneously hypertensive rats","volume":"15","author":"Suetsuna","year":"2004","journal-title":"J. Nutr. Biochem."},{"key":"ref_16","first-page":"163","article-title":"Purification and identification of angiotensin I-converting enzyme inhibitors from the red alga Porphyra yezoensis","volume":"6","author":"Suetsuna","year":"1998","journal-title":"J. Mar. Biotechnol."},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"65","DOI":"10.1016\/j.jff.2016.07.006","article-title":"Isolation and characterization of angiotensin I-converting enzyme (ACE) inhibitory peptides from Ulva rigida C. Agardh protein hydrolysate","volume":"26","author":"Paiva","year":"2016","journal-title":"J. Funct. Foods"},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"7166","DOI":"10.1021\/jf100193f","article-title":"Isolation of an Antihypertensive Peptide from Alcalase Digest of Spirulina platensis","volume":"58","author":"Lu","year":"2010","journal-title":"J. Agric. Food Chem."},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"785","DOI":"10.1016\/j.apjtb.2015.07.012","article-title":"In vitro antimicrobial activities of methanolic extract from marine alga Enteromorpha intestinalis","volume":"5","author":"Ibrahim","year":"2015","journal-title":"Asian Pac. J. Trop. Biomed."},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"247","DOI":"10.1006\/ecss.2001.0900","article-title":"A Model for the Growth of Opportunistic Macroalgae (Enteromorpha sp.) in Tidal Estuaries","volume":"55","author":"Martins","year":"2002","journal-title":"Estuar. Coast. Shelf Sci."},{"key":"ref_21","first-page":"155","article-title":"Mass occurrence of unattached Enteromorpha intestinalis on the Finnish Baltic Sea Coast","volume":"37","author":"Lehvo","year":"2000","journal-title":"Ann. Bot. Fenn."},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"244","DOI":"10.1016\/j.aquabot.2010.08.003","article-title":"Seasonal variation in the mode of reproduction of Ulva intestinalis in a brackish water environment","volume":"93","author":"Leskinen","year":"2010","journal-title":"Aquat. Bot."},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"912","DOI":"10.1016\/j.ijbiomac.2015.09.030","article-title":"Characteristics and antioxidant of Ulva intestinalis sulphated polysaccharides extracted with different solvents","volume":"81","author":"Peasura","year":"2015","journal-title":"Int. J. Biol. Macromol."},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"348","DOI":"10.1016\/j.biortech.2014.03.078","article-title":"Production of reducing sugar from Enteromorpha intestinalis by hydrothermal and enzymatic hydrolysis","volume":"161","author":"Kim","year":"2014","journal-title":"Bioresour. Technol."},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"279","DOI":"10.1016\/j.foodchem.2008.12.019","article-title":"Isolation and characterisation of a novel angiotensin I-converting enzyme (ACE) inhibitory peptide from the algae protein waste","volume":"115","author":"Sheih","year":"2009","journal-title":"Food Chem."},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"43","DOI":"10.1080\/10408690091189266","article-title":"Fish Protein Hydrolysates: Production, Biochemical, and Functional Properties","volume":"40","author":"Kristinsson","year":"2000","journal-title":"Crit. Rev. Food Sci. Nutr."},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"381","DOI":"10.1016\/j.jff.2014.01.021","article-title":"Antihypertensive effect of novel angiotensin I converting enzyme inhibitory peptide from chum salmon (Oncorhynchus keta) skin in spontaneously hypertensive rats","volume":"7","author":"Lee","year":"2014","journal-title":"J. Funct. Foods"},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"170","DOI":"10.1016\/j.lwt.2017.01.010","article-title":"Optimization of a green process for the extraction of lutein and chlorophyll from spinach by-products using response surface methodology (RSM)","volume":"79","author":"Derrien","year":"2017","journal-title":"LWT Food Sci. Technol."},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"36","DOI":"10.1016\/j.foodchem.2005.01.052","article-title":"Purification and identification of angiotensin I-converting enzyme inhibitory peptide from buckwheat (Fagopyrum esculentum Moench)","volume":"96","author":"Ma","year":"2006","journal-title":"Food Chem."},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"490","DOI":"10.1016\/j.procbio.2008.12.017","article-title":"Purification and identification of an angiotensin I-converting enzyme inhibitory peptide from fermented soybean extract","volume":"44","author":"Rho","year":"2009","journal-title":"Process Biochem."},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"332","DOI":"10.1016\/j.jfda.2015.11.010","article-title":"Biochemical characterization of a novel antioxidant and angiotensin I-converting enzyme inhibitory peptide from Struthio camelus egg white protein hydrolysis","volume":"24","author":"Asoodeh","year":"2016","journal-title":"J. Food Drug Anal."},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"9388","DOI":"10.1021\/ac901775h","article-title":"Colorimetric, High-Throughput Assay for Screening Angiotensin I-Converting Enzyme Inhibitors","volume":"81","author":"Jimsheena","year":"2009","journal-title":"Anal. Chem."},{"key":"ref_33","doi-asserted-by":"crossref","first-page":"765","DOI":"10.3390\/nu3090765","article-title":"Bioactive Peptides from Muscle Sources: Meat and Fish","volume":"3","author":"Ryan","year":"2011","journal-title":"Nutrients"},{"key":"ref_34","doi-asserted-by":"crossref","first-page":"358","DOI":"10.1016\/j.lwt.2018.08.045","article-title":"Optimization of ACE inhibitory peptides from black soybean by microwave-assisted enzymatic method and study on its stability","volume":"98","author":"Li","year":"2018","journal-title":"LWT"},{"key":"ref_35","doi-asserted-by":"crossref","first-page":"495","DOI":"10.1016\/j.foodchem.2010.09.039","article-title":"Effect of angiotensin I converting enzyme inhibitory peptide purified from skate skin hydrolysate","volume":"125","author":"Lee","year":"2011","journal-title":"Food Chem."},{"key":"ref_36","doi-asserted-by":"crossref","first-page":"1075","DOI":"10.1016\/j.idairyj.2004.04.007","article-title":"Angiotensin converting enzyme-inhibitory activity of peptides isolated from Manchego cheese. Stability under simulated gastrointestinal digestion","volume":"14","author":"Ruiz","year":"2004","journal-title":"Int. Dairy J."},{"key":"ref_37","doi-asserted-by":"crossref","first-page":"7","DOI":"10.1007\/s00217-007-0689-6","article-title":"Antihypertensive and antimicrobial bioactive peptides from milk proteins","volume":"227","author":"Haque","year":"2008","journal-title":"Eur. Food Res. Technol."},{"key":"ref_38","doi-asserted-by":"crossref","unstructured":"Yu, F., Zhang, Z., Luo, L., Zhu, J., Huang, F., Yang, Z., Tang, Y., and Ding, G. (2018). Identification and Molecular Docking Study of a Novel Angiotensin-I Converting Enzyme Inhibitory Peptide Derived from Enzymatic Hydrolysates of Cyclina sinensis. Mar. Drugs, 16.","DOI":"10.3390\/md16110411"},{"key":"ref_39","doi-asserted-by":"crossref","first-page":"367","DOI":"10.1016\/S0963-9969(01)00131-4","article-title":"Characterization of inhibition and stability of soy-protein-derived angiotensin I-converting enzyme inhibitory peptides","volume":"35","author":"Wu","year":"2002","journal-title":"Food Res. Int."},{"key":"ref_40","doi-asserted-by":"crossref","first-page":"1622","DOI":"10.1016\/j.procbio.2016.07.006","article-title":"Angiotensin- I- converting enzyme (ACE) inhibitory peptides from Pacific cod skin gelatin using ultrafiltration membranes","volume":"51","author":"Ngo","year":"2016","journal-title":"Process Biochem."},{"key":"ref_41","doi-asserted-by":"crossref","first-page":"696","DOI":"10.1016\/j.jfda.2017.07.008","article-title":"Production of antioxidant and ACE-inhibitory peptides from Kluyveromyces marxianus protein hydrolysates: Purification and molecular docking","volume":"26","author":"Mirzaei","year":"2018","journal-title":"J. Food Drug Anal."},{"key":"ref_42","doi-asserted-by":"crossref","first-page":"4364","DOI":"10.1016\/j.bmcl.2009.05.079","article-title":"Effect of varying chain length between P1 and P1\u2032 position of tripeptidomimics on activity of angiotensin-converting enzyme inhibitors","volume":"19","author":"Chaudhary","year":"2009","journal-title":"Bioorg. Med. Chem. Lett."},{"key":"ref_43","doi-asserted-by":"crossref","first-page":"17","DOI":"10.1016\/j.peptides.2014.07.026","article-title":"A novel angiotensin-I converting enzyme (ACE) inhibitory peptide from gastrointestinal protease hydrolysate of silkworm pupa (Bombyx mori) protein: Biochemical characterization and molecular docking study","volume":"68","author":"Wu","year":"2015","journal-title":"Peptides"},{"key":"ref_44","doi-asserted-by":"crossref","first-page":"145","DOI":"10.1016\/j.procbio.2017.04.032","article-title":"In silico analysis and antihypertensive effect of ACE-inhibitory peptides from smooth-hound viscera protein hydrolysate: Enzyme-peptide interaction study using molecular docking simulation","volume":"58","author":"Abdelhedi","year":"2017","journal-title":"Process Biochem."},{"key":"ref_45","doi-asserted-by":"crossref","first-page":"359","DOI":"10.1016\/j.jprot.2013.10.006","article-title":"A novel angiotensin converting enzyme inhibitory peptide derived from proteolytic digest of Chinese soft-shelled turtle egg white proteins","volume":"94","author":"Rawendra","year":"2013","journal-title":"J. Proteom."},{"key":"ref_46","doi-asserted-by":"crossref","first-page":"3898","DOI":"10.1016\/j.bmcl.2011.05.033","article-title":"The molecular mechanisms of interactions between bioactive peptides and angiotensin-converting enzyme","volume":"21","author":"Pan","year":"2011","journal-title":"Bioorg. Med. Chem. Lett."},{"key":"ref_47","doi-asserted-by":"crossref","first-page":"351","DOI":"10.1007\/s10811-014-0347-x","article-title":"Hydrolysis and purification of ACE inhibitory peptides from the marine microalga Isochrysis galbana","volume":"27","author":"Wu","year":"2015","journal-title":"J. Appl. Phycol."},{"key":"ref_48","doi-asserted-by":"crossref","first-page":"178","DOI":"10.1017\/S0022029905001639","article-title":"Performance of two commonly used angiotensin-converting enzyme inhibition assays using FA-PGG and HHL as substrates","volume":"73","author":"Shalaby","year":"2006","journal-title":"J. Dairy Res."},{"key":"ref_49","doi-asserted-by":"crossref","first-page":"10685","DOI":"10.1021\/jf403004e","article-title":"Measuring Angiotensin-I Converting Enzyme Inhibitory Activity by Micro Plate Assays: Comparison Using Marine Cryptides and Tentative Threshold Determinations with Captopril and Losartan","volume":"61","author":"Henda","year":"2013","journal-title":"J. Agric. Food Chem."},{"key":"ref_50","doi-asserted-by":"crossref","first-page":"410","DOI":"10.1021\/jf072277p","article-title":"Investigations into Inhibitor Type and Mode, Simulated Gastrointestinal Digestion, and Cell Transport of the Angiotensin I-Converting Enzyme\u2013Inhibitory Peptides in Pacific Hake (Merluccius productus) Fillet Hydrolysate","volume":"56","author":"Hu","year":"2008","journal-title":"J. Agric. Food Chem."}],"container-title":["Marine Drugs"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1660-3397\/17\/3\/179\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T12:39:04Z","timestamp":1760186344000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1660-3397\/17\/3\/179"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2019,3,19]]},"references-count":50,"journal-issue":{"issue":"3","published-online":{"date-parts":[[2019,3]]}},"alternative-id":["md17030179"],"URL":"https:\/\/doi.org\/10.3390\/md17030179","relation":{},"ISSN":["1660-3397"],"issn-type":[{"value":"1660-3397","type":"electronic"}],"subject":[],"published":{"date-parts":[[2019,3,19]]}}}