College of Food Science and Technology, Bohai University, Food Safety Key Laboratory of Liaoning Province, National & Local Joint Engineering Research Center for Storage, Processing and Safety Control Technology for Fresh Agricultural and Aquatic Products, Jinzhou 121013, China.
College of Food Science and Technology, Bohai University, Food Safety Key Laboratory of Liaoning Province, National & Local Joint Engineering Research Center for Storage, Processing and Safety Control Technology for Fresh Agricultural and Aquatic Products, Jinzhou 121013, China.
Food Chem. 2022 Mar 30;373(Pt B):131559. doi: 10.1016/j.foodchem.2021.131559. Epub 2021 Nov 9.
Trimethylamine-N-oxide demethylase (TMAOase) is a key enzyme for the decomposition of trimethylamine oxide into formaldehyde. The study investigated the inhibitory effects of (+)-catechin on TMAOase and involved mechanism to minimize the formaldehyde (FA) content of seafood during storage. TMAOase was purified by DEAE-52 cellulose and Sephacryl S-300 chromatography and the inhibitory mechanism of TMAOase was studied by Lineweaver-Burk plots, fluorescence spectroscopy, and circular dichroism. Specific activity of 37 ± 0.7 U/mg was obtained with 205 -fold purification and 15% yield, and molecular mass was 25 kDa. (+)-Catechin was a reversible inhibitor of TMAOase and its induced mechanism was the non-competitive inhibition type. (+)-Catechin binding to TMAOase formed a complex with the binding constant (K) of 0.72 × 10 at 298 K. The formation of complex induced the static fluorescence quenching and changes in the conformation of TMAOase, leading to a reduction in the rate of catalysis.
三甲胺 N-氧化物脱甲基酶（TMAOase）是分解三甲胺氧化物生成甲醛的关键酶。本研究探讨了（+）-儿茶素对 TMAOase 的抑制作用及其机制，以在储存过程中最大限度地减少海鲜中的甲醛（FA）含量。通过 DEAE-52 纤维素和 Sephacryl S-300 层析法对 TMAOase 进行纯化，并通过 Lineweaver-Burk 图谱、荧光光谱和圆二色性研究 TMAOase 的抑制机制。获得了 37±0.7 U/mg 的比活性，纯化倍数为 205 倍，产率为 15%，分子量为 25 kDa。（+）-儿茶素是 TMAOase 的可逆抑制剂，其诱导机制是非竞争性抑制类型。（+）-儿茶素与 TMAOase 结合形成复合物，在 298 K 时结合常数（K）为 0.72×10。复合物的形成诱导了 TMAOase 的静态荧光猝灭和构象变化，从而降低了催化速率。
