Inhibitory mechanism of ethyl furaneol on polyphenol oxidase: Kinetics, structural changes, and molecular docking analysis
Xiongfeng Zhang, Yuhao Huang, Xiaoyong Chang, Xing Lu, Shaohe Jiao, Ruixi Bai, Yan Chen, Junping Liu, Lei ZhouAbstract
Background
Enzymatic browning catalyzed by polyphenol oxidase (PPO) severely compromises the quality and economic value of tobacco leaves. However, research on inhibiting tobacco browning using natural extracts remains limited.
Results
This study initially screened four cultivars and identified ‘YY73’ with the highest PPO activity (37 OD min −1 ), which was subsequently used as the subject for PPO activity assessment. Among eight natural compounds tested at 0.1 g L −1 , ethyl furaneol and kaempferol achieved nearly complete inhibition. In a further concentration gradient experiment, ethyl furaneol exhibited an IC 50 of 0.0174 g L −1 and completely inhibited enzymatic activity at 0.06 g L −1 , outperforming kaempferol. Inhibitory kinetic analysis revealed that ethyl furaneol acts as a reversible mixed‐type inhibitor with competitive dominance. Fluorescence spectroscopy confirmed that ethyl furaneol induces conformational changes, and the static quenching constant verified the formation of a ground‐state complex. Molecular docking simulations indicated that ethyl furaneol embeds into the active site cavity of PPO, forming van der Waals forces and π ‐alkyl interactions with key residues, thereby potentially disrupting substrate binding and inhibiting catalytic activity.
Conclusion
This study demonstrates that ethyl furaneol is a promising inhibitor of tobacco leaf PPO, elucidates its mechanism of action against tobacco leaf PPO and provides a new strategy for the environmentally friendly control of enzymatic browning in tobacco leaves during agricultural processing.