Novel strategy to improve the bioactivity and anti-hydrolysis ability of oat peptides via zinc ion-induced assembling

• Published in: Food chemistry 2023-08, Vol.416, p.135468-135468, Article 135468
• Main Authors: Zhang, Junping, Tang, Yingxue, Zhou, Saiping, Yin, Xiaoyu, Zhuang, Xueying, Ren, Yanan, Chen, Xiangning, Fan, Junfeng, Zhang, Yanyan
• Format: Article
• Language: English
• Subjects: Avena; Bioaccessibility; Inhibition dynamics; Lipase inhibition; Metals - chemistry; Peptide Hydrolases; Peptides - chemistry; Peptides - pharmacology; Peptides-Zn chelate; Protease; Self-assembling; Zinc - chemistry
• ISSN: 0308-8146; 1873-7072
• DOI: 10.1016/j.foodchem.2023.135468

•We first use metal chelation to promote protease resistance of bioactive peptides.•Zn coordination greatly protects bioactive peptides from protease hydrolysis.•Zn chelation greatly enhances the lipase (PL) inhibitory activity of oat peptides.•Peptide-Zn complex (PC) aptly binds to PL due to high hydrophobicity and low charge.•PC is high soluble and orderly eutectic and thus has high protease resistance. This study aims to use metal ion coordinating method to improve the bioactivity and anti-hydrolysis ability of bioactive peptides. We demonstrated that zinc (Zn) coordination (10:1 mass ratio of peptide to Zn, pH 6.8, 37 °C) induced assembly of oat peptides, improved pancreatic lipase (PL) inhibitory activity by 30.4–36.8 % and anti-hydrolysis ability against intestinal proteases by 26.5–38.2 %; meanwhile, the peptide-Zn complex drastically reduced the PL affinity to the substrate. Detailed mechanism analysis showed that the high hydrophobicity (276 of fluorescent intensity) and dense eutectic structure of peptide-Zn complexes caused the hard hydrolysis of complexed peptides by proteases; in particular, the neutralized surface charges (∼−3.6 mV) of complexes imparted the peptide-Zn complex high affinity towards PL (–22.3 mV) thus robust PL inhibitory activity. These findings deepened our understanding of the interaction of peptides with metal elements and set the groundwork for the enhancement and protection of bioactive peptides.