School of Science, Xihua University, Chengdu, P. R. China.
Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu, P. R. China.
J Sep Sci. 2022 Sep;45(18):3635-3645. doi: 10.1002/jssc.202200303. Epub 2022 Jul 28.
In this study, tyrosinase was immobilized on carboxyl functionalized silica-coated magnetic nanoparticles for the first time to be used for fishing of tyrosinase's ligands present in complex plant extract. The immobilized tyrosinase was characterized by transmission electron microscopy, vibrating sample magnetometry, Fourier transform infrared spectroscopy, thermo-gravimetric analyzer, and atomic force microscopy. The reusability and thermostability of the immobilized tyrosinase were found significantly superior to its free counterpart. Two tyrosinase's ligands, that is, caffeic acid (1) and rosmarinic acid (2), were fished out from extract of the traditional Chinese medicine Prunellae Spica by the immobilized tyrosinase. Compound 1 was found to be an activator of the enzyme with the half maximal effective concentration value of 0.27 ± 0.06 mM, while compound 2 was an inhibitor with the half maximal inhibitory concentration value of 0.14 ± 0.03 mM. Taking advantage of the convenience of magnetic separation and specific extraction ability of ligand fishing, the proposed method exhibited great potential for screening of bioactive compounds from complex matrices.
在这项研究中，酪氨酸酶首次被固定在羧基功能化的硅烷涂层磁性纳米颗粒上，用于从复杂植物提取物中钓取酪氨酸酶的配体。固定化酪氨酸酶的特征通过透射电子显微镜、振动样品磁强计、傅里叶变换红外光谱、热重分析仪和原子力显微镜进行了描述。固定化酪氨酸酶的可重复使用性和热稳定性明显优于游离酶。两种酪氨酸酶的配体，即咖啡酸（1）和迷迭香酸（2），通过固定化酪氨酸酶从中药夏枯草提取物中钓出。发现化合物 1 是该酶的激活剂，半数有效浓度值为 0.27 ± 0.06 mM，而化合物 2 是抑制剂，半数最大抑制浓度值为 0.14 ± 0.03 mM。利用磁性分离的便利性和配体钓取的特异性提取能力，该方法在从复杂基质中筛选生物活性化合物方面显示出巨大的潜力。
