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Updated: Sep 18, 2025

Structural Biology and Analytical Chemistry Approaches for Characterizing C-Glycoside Metabolic Enzymes in Human Gut Microbiota
Published on: May 23, 2025
Influence of catechin-PAYCS interactions on gastrointestinal structural and bioactivity stability: Key mechanisms in
Jieqiong Chen1, Chunyan Lin2, Lijia Yang3
1Sericulture & Agri-food Research Institute Guangdong Academy of Agricultural Sciences, Key Laboratory of Functional Foods, Ministry of Agriculture and Rural affairs, Guangdong Key Laboratory of Agricultural Products Processing, Guangzhou, Guangdong 510610, China; School of Food Science and Engineering, South China University of Technology, Guangzhou 510640, China.
Abstract:
Food-derived bioactive peptides often show instability during digestion, limiting their functional application. Polyphenols can enhance peptide stability via covalent or non-covalent interactions, influencing structure, activity, and digestion behavior. This study investigated catechin (CA) interactions with PAYCS (Pro-Ala-Tyr-Cys-Ser) and their effects on digestive stability and enzyme modulation. Covalent (CA-PS) and non-covalent (CA/PS) complexes were prepared via alkaline and physical treatments. Spectroscopic analysis confirmed distinct binding modes, altering structural stability and fluorescence properties. SEM and particle size analysis revealed that CA-PS formed a more stable network. Digestion studies demonstrated that CA/PS better resisted gastric digestion, while CA-PS exhibited greater stability in the intestine. Under simulated digestion conditions, CA/PS complexes use mixed-type pepsin inhibition to preserve structure in the stomach, while CA-PS employ competitive trypsin inhibition to retain activity in the intestine. These findings suggest polyphenol-peptide interactions modulate peptide digestion and functional activity, providing insights for enhancing bioactive peptide stability in functional foods.
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