He Jian-Ju, Liu Xin-Xin, Li Ying, Wang Zhe, Shi Hong-Ling, Kan Yun-Chao, Yao Lun-Guang, Tang Cun-Duo
Henan Provincial Key Laboratory of Funiu Mountain Insect Biology and Henan Provincal Engineering and Technology Center of Health Products for Livestock and Poultry, Nanyang Normal University, Nanyang, China.
College of Life Science and Agricultural Engineering, Nanyang Normal University, Nanyang, China.
Front Bioeng Biotechnol. 2023 Feb 15;11:1134152. doi: 10.3389/fbioe.2023.1134152. eCollection 2023.
Nicotinamide riboside kinase (NRK) plays an important role in the synthesis of β -nicotinamide nucleotide (NMN). NMN is a key intermediate of NAD synthesis, and it actually contribute to the well-being of our health. In this study, gene mining technology was used to clone nicotinamide nucleoside kinase gene fragments from , and the NRK1 was achieved a high level of soluble expression in E. coli BL21. Then, the reScNRK1 was immobilized by metal affinity label to optimize the enzyme performance. The results showed that the enzyme activity in the fermentation broth was 14.75 IU/mL, and the specific enzyme activity after purification was 2252.59 IU/mg. After immobilization, the optimum temperature of the immobilized enzyme was increased by 10°C compared with the free enzyme, and the temperature stability was improved with little change in pH. Moreover, the activity of the immobilized enzyme remained above 80% after four cycles of immobilized reScNRK1, which makes the enzyme more advantageous in the enzymatic synthesis of NMN.
烟酰胺核糖激酶（NRK）在β-烟酰胺核苷酸（NMN）的合成中起重要作用。NMN是NAD合成的关键中间体，实际上对我们的健康有益。在本研究中，利用基因挖掘技术从……克隆烟酰胺核苷激酶基因片段，NRK1在大肠杆菌BL21中实现了高水平的可溶性表达。然后，通过金属亲和标签固定化重组ScNRK1以优化酶性能。结果表明，发酵液中的酶活性为14.75 IU/mL，纯化后的比酶活性为2252.59 IU/mg。固定化后，固定化酶的最适温度比游离酶提高了10°C，温度稳定性得到改善，pH变化不大。此外，固定化重组ScNRK1经过四次循环后，固定化酶的活性仍保持在80%以上，这使得该酶在NMN的酶促合成中更具优势。
