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Updated: Jun 18, 2026

A Fluorescence-based Protocol for Preliminary Screening of Protein Synthesis Inhibitors from Natural Sources
Published on: January 27, 2026
Inhibition of protein-bound heterocyclic amines by citrus polymethoxyflavones via stabilizing myofibrillar protein
Hui Xin1, Diaodiao Yang2, Shigang Liu1
1College of Food Science and Technology, Hunan Agricultural University, Changsha, Hunan 410128, China.
Abstract:
This study investigated how citrus polymethoxyflavones (PMFs)-isosinensetin (ISN), tangeretin (TG), 3',4',5,7-tetramethoxyflavone (TMHF), and their mixture (MIX) inhibit protein-bound heterocyclic amines (HAs) by modulating myofibrillar protein (MP) structure. In roasted beef, ISN and MIX reduced bound HAs by 56.1% and 75.5%, respectively, outperforming TG and TMHF. Mechanistic studies in model systems ruled out direct HA-PMF reactions and suggested competitive binding of PMFs to MP. This interaction quenched MP fluorescence, suppressed heat-induced aggregation, decreased reactive amino and sulfhydryl groups, and preserved MP's native-like secondary structure (higher α-helix) and compactness (lower Rg). Molecular dynamics simulations confirmed stable binding of ISN and MIX to myosin. The superior efficacy of ISN and MIX arises from broader chemical masking of reactive residues, favorable binding sites, and enhanced thermal conformational stability. These findings establish structure-activity relationship for citrus PMFs and provide a protein-targeted mechanistic basis for their use as functional ingredients in safer thermally processed meats.
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