Different modes of inhibition for organic acids on polyphenoloxidase
Different modes of inhibition for organic acids on polyphenoloxidase
复制标题
有机酸对多酚氧化酶的不同抑制方式
DOI：
10.1016/j.foodchem.2015.12.034
复制
发表时间：
2016
期刊：
影响因子：
8.8
通讯作者：
Zhong Junzhen
中科院分区：
文献类型：
--
作者：
Zhou Lei;Liu Wei;Xiong Zhiqiang;Zou Liqiang;Chen Jun;Liu Junping;Zhong Junzhen
有机酸对多酚氧化酶（PPO）的抑制作用是通过可逆性抑制还是通过降低pH实现的，目前还不清楚。结果表明，肉桂酸对葡萄糖的抑制作用是可逆的，柠檬酸和苹果酸对葡萄糖的抑制作用主要是由于pH值的降低。动力学结果表明，肉桂酸对多酚氧化酶的抑制作用为可逆的混合型。荧光发射光谱表明，肉桂酸可能与PPO发生相互作用，使其内源荧光猝灭，而柠檬酸和苹果酸引起的荧光强度下降则与pH有关，肉桂酸与PPO发生结合，引起二级结构重排。分子对接结果表明，肉桂酸以π-π堆积的方式插入到PPO的疏水空腔中。
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 π–π stacking.