Mushroom (Agaricus bisporus) polyphenoloxidase inhibited by apigenin: Multi-spectroscopic analyses and computational docking simulation

• Published in: Food chemistry Vol. 203; pp. 430 - 439
• Main Authors: Xiong, Zhiqiang, Liu, Wei, Zhou, Lei, Zou, Liqiang, Chen, Jun
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 15.07.2016
• Subjects: activation energy; Agaricus - enzymology; Agaricus bisporus; amino acids; Apigenin; Apigenin - chemistry; Apigenin - pharmacology; atomic force microscopy; catechol oxidase; Catechol Oxidase - antagonists & inhibitors; Catechol Oxidase - chemistry; Circular Dichroism; circular dichroism spectroscopy; Computational docking simulation; enzymatic browning; Enzyme Stability; fluorescence; Fruit - chemistry; fruits; Hydrophobic and Hydrophilic Interactions; hydrophobicity; Inhibition mechanism; Kinetics; Molecular Docking Simulation; mushrooms; Polyphenoloxidase; polyphenols; Polyphenols - pharmacology; Protein Binding; Protein Conformation; Spectrophotometry, Ultraviolet; synergism; Thermodynamic parameters; Thermodynamics; Vegetables - chemistry; Thermodynamic parameters; Computational docking simulation; Apigenin; Polyphenoloxidase; Inhibition mechanism
• ISSN: 0308-8146; 1873-7072; 1873-7072
• DOI: 10.1016/j.foodchem.2016.02.045

•Polyphenoloxidase activity was inhibited by apigenin in a mixed-type manner.•The thermosensitivity of polyphenoloxidase decreased after treating with apigenin.•The dimension of apigenin treated polyphenoloxidase molecules became larger.•The conformations of polyphenoloxidase changed after treating with apigenin.•Two docking simulation software verified that apigenin bound to polyphenoloxidase. It has been revealed that some polyphenols can prevent enzymatic browning caused by polyphenoloxidase (PPO). Apigenin, widely distributed in many fruits and vegetables, is an important bioactive flavonoid compound. In this study, apigenin exhibited a strong inhibitory activity against PPO, and some reagents had synergistic effect with apigenin on inhibiting PPO. Apigenin inhibited PPO activity reversibly in a mixed-type manner. The fact that inactivation rate constant (k) of PPO increased while activation energy (Ea) and thermodynamic parameters (ΔG, ΔH and ΔS) decreased indicated that the thermosensitivity and stability of PPO decreased. The conformational changes of PPO were revealed by fluorescence emission spectra and circular dichroism. Atomic force microscopy observation suggested that the dimension of PPO molecules was larger after interacting with apigenin. Moreover, computational docking simulation indicated that apigenin bound to PPO and inserted into the hydrophobic cavity of PPO to interact with some amino acid residues.