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Noncovalent Interaction-Driven Assembly Endows Casein Amyloid Fibrils with Inhibitory Activities against
Mengqing Li1, Siyu Zhang1, Yan Liu2
1College of Food Science and Engineering, Northwest A & F University, Yangling 712100, China.
Journal of Agricultural and Food Chemistry
|January 3, 2026
Summary
Casein amyloid fibrils (CNAF) enhance inhibition of starch-hydrolyzing enzymes. This structure-specific interaction effectively delays starch digestion, suggesting CNAF as a functional ingredient for glycemic regulation.
Area of Science:
- Biochemistry
- Materials Science
Background:
- Casein possesses amphiphilic and self-assembling properties.
- Casein can transform into amyloid fibrils (CNAF) with unique bioactivity.
Purpose of the Study:
- To investigate the impact of casein fibrillation on its inhibitory activity against starch-hydrolyzing enzymes.
- To elucidate the mechanism behind the enhanced enzyme inhibition by CNAF.
Main Methods:
- Casein fibrillation monitored using thioflavin T fluorescence kinetics.
- Conformational analysis of casein and CNAF.
- Enzyme kinetics studies with α-amylase and α-glucosidase.
- Assessment of in vitro starch digestion.
Main Results:
- Casein fibrillation significantly enhanced inhibitory activity against starch-hydrolyzing enzymes.
- CNAF formation involved a conformational transition to β-sheet-rich structures.
- CNAF's morphology (high aspect ratio, large surface area) facilitated multivalent enzyme binding.
- CNAF exhibited mixed-type inhibition of α-amylase and competitive inhibition of α-glucosidase.
- CNAF effectively delayed in vitro starch digestion.
Conclusions:
- Casein fibrillation transforms casein into CNAF with potent enzyme inhibitory properties.
- CNAF's structure dictates its specific enzyme inhibition mechanisms.
- CNAF demonstrates potential as a functional ingredient for managing postprandial glycemic responses.
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