Different modes of inhibition for organic acids on polyphenoloxidase

卷:199

Zhou, Lei ; Liu, Wei ; Xiong, Zhiqiang ; Zou, Liqiang ; Chen, Jun ; Liu, Junping ; Zhong, Junzhen

Nanchang Univ

关键词: Polyphenoloxidase;    Organic acid;    pH;    Inhibitory mode;    Conformation;    Molecular docking;   

DOI  :  10.1016/j.foodchem.2015.12.034

学科分类：食品科学和技术

【 摘 要 】

It is still unclear whether the inhibitory effect of organic acid on polyphenoloxidase (PPO) is due to the reversible inhibition or decrease of pH. In this study, cinnamic acid, citric acid and malic acid inhibited PPO in different modes. Results showed that the inhibition by cinnamic acid resulted from reversible inhibition, while the decrease of pH was the main cause for citric acid and malic acid. The kinetic results showed that cinnamic acid reversibly inhibited PPO in a mixed-type manner. Fluorescence emission spectra indicated that cinnamic acid might interact with PPO and quench its intrinsic fluorescence, while the decrease of the fluorescence intensity induced by citric acid or malic acid was due to the acid-pH. Cinnamic acid bound to PPO and induced the rearrangement of secondary structure. Molecular docking result revealed cinnamic acid inserted into the hydrophobic cavity of PPO by forming p-p stacking. Crown Copyright (C) 2015 Published by Elsevier Ltd. All rights reserved.