Lü Xiao-Feng, Feng Chao-Yun, Li Shuangfei, Liu Guo-Hao, Yang Zhen
College of Life Sciences and Oceanography, Shenzhen Key Laboratory of Microbial Genetic Engineering, Shenzhen University, 1066 Xue Yuan Avenue, Shenzhen, 518055, Guangdong, China.
College of Life Sciences and Oceanography, Shenzhen Key Laboratory of Marine Bioresources and Eco-Environmental Science, Shenzhen University, Shenzhen, 518055, Guangdong, China.
Bioresour Bioprocess. 2021 Oct 27;8(1):108. doi: 10.1186/s40643-021-00462-7.
Although metal-organic frameworks (MOFs) have been considered as promising matrices for enzyme immobilization, HKUST-1, constructed from copper acetate (CuAc) and benzene 1,3,5-tricarboxylate (BTC), has rarely been explored for this application. In this study, mushroom tyrosinase (EC 1.14.18.1) was immobilized in the form of tyrosinase@HKUST-1 following a simple reaction procedure by mixing BTC with the enzyme prior to addition of CuAc. The resultant biocatalyst was characterized in both structural features and catalytic properties. Upon incorporation into the HKUST-1 frameworks, the enzyme gained a prominent enhancement in stability against pH, temperature and storage: When incubated at 50 °C and pH 6.0, tyrosinase@HKUST-1 presented a half-life of 32.6 h, which is 77-fold and over tenfold higher than that of the free enzyme and its other immobilization forms, respectively; and the catalyst fully maintained its activity for at least 2 months when stored at 30 °C. The applicability of this new biocatalyst was demonstrated by employing it as catalyst for regioselective ortho-hydroxylation reactions to produce catecholic products with huge pharmacological effects, i.e., hydroxytyrosol and L-DOPA, with excellent yields and productivities. This study has thus offered a facile immobilization method to prepare a novel biocatalyst with super stability, and tyrosinase@HKUST-1 so formed from crude mushroom extract provides an efficient catalyst which can be applied to the production of catecholic products with health benefits.
尽管金属有机框架材料（MOFs）被认为是用于酶固定化的有前景的基质，但由醋酸铜（CuAc）和均苯三甲酸（BTC）构建的HKUST-1在该应用方面却鲜有探索。在本研究中，通过在添加CuAc之前将BTC与蘑菇酪氨酸酶混合，按照简单的反应程序将蘑菇酪氨酸酶（EC 1.14.18.1）固定为酪氨酸酶@HKUST-1形式。对所得生物催化剂的结构特征和催化性能进行了表征。掺入HKUST-1框架后，该酶在抗pH、温度和储存稳定性方面有显著提高：在50°C和pH 6.0下孵育时，酪氨酸酶@HKUST-1的半衰期为32.6小时，分别比游离酶及其其他固定化形式高77倍和十倍以上；并且该催化剂在30°C储存时至少2个月能完全保持其活性。通过将这种新型生物催化剂用作区域选择性邻位羟基化反应的催化剂，以优异的产率和生产率生产具有巨大药理作用的儿茶酚产物，即羟基酪醇和L-多巴，证明了其适用性。因此，本研究提供了一种简便的固定化方法来制备具有超稳定性的新型生物催化剂，由粗蘑菇提取物形成的酪氨酸酶@HKUST-1提供了一种可应用于生产具有健康益处的儿茶酚产物的高效催化剂。
