Faculty of Food Science and Engineering, Kunming University of Science and Technology, Kunming, Yunnan Province 650500, China.
Faculty of Food Science and Engineering, Kunming University of Science and Technology, Kunming, Yunnan Province 650500, China.
Food Chem. 2023 Jan 30;400:134048. doi: 10.1016/j.foodchem.2022.134048. Epub 2022 Aug 30.
The inhibition mechanisms of soluble PPO (sPPO) by l-cysteine, reduced glutathione and thiourea, and membrane-bound (mPPO) by l-cysteine, reduced glutathione, thiourea, anisaldehyde and cinnamaldehyde were investigated by combining multispectroscopic analysis and computational simulations. Reduced glutathione showed the strongest inhibitory effect, with IC50 of 0.46 and 0.94 mM, respectively. The multispectral results showed that all inhibitors inhibited activity by destroying the secondary and tertiary structure, and the structure of sPPO were more easily affected. Docking showed that hydrogen bond and metal contact were the main driving force for inhibitors binding to sPPO and mPPO, respectively. Simulation showed that sPPO-inhibitor system had more fluctuation than mPPO-inhibitor system, indicating easier inhibition of sPPO activity. This work revealed that the structural differences between sPPO and mPPO led to different inhibition mechanisms of PPOs by inhibitors at the molecular level, which could provide the guidance for the selection of inhibitors in fruit and vegetable processing.
通过结合多谱学分析和计算模拟，研究了 l-半胱氨酸、还原型谷胱甘肽和硫脲对可溶性多酚氧化酶（sPPO）的抑制机制，以及 l-半胱氨酸、还原型谷胱甘肽、硫脲、香草醛和肉桂醛对膜结合多酚氧化酶（mPPO）的抑制机制。还原型谷胱甘肽的抑制作用最强，IC50 分别为 0.46 和 0.94 mM。多谱学结果表明，所有抑制剂均通过破坏二级和三级结构来抑制活性，sPPO 的结构更容易受到影响。对接表明氢键和金属接触分别是抑制剂与 sPPO 和 mPPO 结合的主要驱动力。模拟表明，sPPO-抑制剂体系比 mPPO-抑制剂体系具有更多的波动，表明 sPPO 活性更容易被抑制。这项工作揭示了 sPPO 和 mPPO 之间的结构差异导致了抑制剂在分子水平上对多酚氧化酶抑制机制的不同，为果蔬加工中抑制剂的选择提供了指导。
