Preparation, identification, and molecular docking of novel angiotensin‐converting enzyme inhibitory peptides derived from rice‐based distillers' spent cakes

• Published in: Journal of the science of food and agriculture Vol. 104; no. 11; pp. 6506 - 6517
• Main Authors: Su, Hanxing, Fan, Wenlai, Xu, Yan, Tang, Shaopei, Yue, Dehong, Liao, Zuyue
• Format: Journal Article
• Language: English
• Published: Chichester, UK John Wiley & Sons, Ltd 30.08.2024; John Wiley and Sons, Limited
• Subjects: ACE; Active control; Amino acids; Angiotensin; Cakes; Chinese sweet and honey aroma and flavor liquor (Baijiu); Enzymes; Functional foods & nutraceuticals; Hypertension; in silico; Liquid chromatography; Mass spectrometry; Mass spectroscopy; Molecular docking; Peptides; peptidomics; Quadrupoles; RDSC; Residues; Rice; rice‐based distillers' spent wash; Subtilisin; Ultrafiltration; rice‐based distillers' spent wash; ACE; in silico; RDSC; peptidomics; Chinese sweet and honey aroma and flavor liquor (Baijiu)
• ISSN: 0022-5142; 1097-0010; 1097-0010
• DOI: 10.1002/jsfa.13474

BACKGROUND Rice‐based distillers' spent cake (RDSC), a by‐product of the Chinese liquor (Baijiu) industry, is a potential source of angiotensin‐converting enzyme (ACE) inhibitory peptide. Since ACE plays a crucial role in controlling hypertension, inhibition of ACE has been widely emphasized. The ACE inhibitory active peptide derived from by‐products of food has been recognized as a safer and cheaper inhibitor. RESULTS Aimed to discover ACE‐inhibiting active peptides in RDSC. Hydrolysis of RDSC by alcalase for 4 h followed by ultrafiltration yielded low‐molecular‐weight (< 3 kDa) fractions. Subsequently, a comprehensive method using a combination of liquid chromatography quadrupole time‐of‐flight mass spectrometry (LC‐Q‐TOF‐MS) and LC‐Q‐Exactive‐MS to identify the novel short peptides (3–5 amino acids residues; n = 7) and medium‐sized peptides (more than 6 amino acids residues; n = 6). In vitro activity assay showed that the peptides KPFFPGL, GFPRPLL, GPPGVF, and VGK exhibited the highest activity with inhibitory concentration of 50% (IC50) of 11.63, 12.34, 19.55, and 33.54 μmol L−1. Molecular docking reveal that the active and inactive sites (Glu123, Asp121, Arg522, and Lys118) play important roles in enhancing the ACE inhibitory activity of peptides. CONCLUSION Here we report a comprehensive method that effectively extracted and identified the bioactive peptides from RDSC. Four highly active novel peptides may be the most promising candidates for functional foods against hypertension, provide significant information for enhancing value of rice‐based distilled by‐products. © 2024 Society of Chemical Industry.