Shenzhen Raink Ecology & Environment Co., Ltd., Shenzhen 518102, China.
School of Food Science and Engineering, South China University of Technology, Guangzhou 510640, China.
Mar Drugs. 2023 May 29;21(6):332. doi: 10.3390/md21060332.
The enzymatic degradation of different chitin polymers into chitin oligosaccharides (COSs) is of great significance given their better solubility and various biological applications. Chitinase plays a pivotal role in the enzymatic preparation of COSs. Herein, a cold-adapted and efficient chitinase (ChiTg) from the marine R1 was purified and characterized. The optimal temperature of ChiTg was 40 °C, and the relative activity at 5 °C was above 40.1%. Meanwhile, ChiTg was active and stable from pH 4.0 to 7.0. As an endo-type chitinase, ChiTg exhibited the highest activity with colloidal chitin, then with ball-milled and powdery chitin. In addition, ChiTg showed high efficiency when hydrolyzing colloidal chitin at different temperatures, and the end products were mainly composed of COSs with one to three degrees of polymerization. Furthermore, the results of bioinformatics analysis revealed that ChiTg belongs to the GH18 family, and its acidic surface and the flexible structure of its catalytic site may contribute to its high activity in cold conditions. The results of this study provide a cold-active and efficient chitinase and ideas for its application regarding the preparation of COSs from colloidal chitin.
鉴于其更好的溶解性和各种生物应用，将不同的壳聚糖聚合物酶解成壳寡糖（COSs）具有重要意义。壳聚糖酶在 COSs 的酶法制备中起着关键作用。本文从海洋 R1 中纯化和表征了一种耐冷且高效的壳聚糖酶（ChiTg）。ChiTg 的最适温度为 40°C，在 5°C 时的相对活性超过 40.1%。同时，ChiTg 在 pH 值 4.0 到 7.0 之间保持活性和稳定。作为一种内切型壳聚糖酶，ChiTg 对胶体壳聚糖表现出最高的活性，其次是球磨和粉末状壳聚糖。此外，ChiTg 在不同温度下水解胶体壳聚糖时效率很高，终产物主要由聚合度为一到三的 COSs 组成。此外，生物信息学分析的结果表明 ChiTg 属于 GH18 家族，其酸性表面和催化部位的柔性结构可能有助于其在低温下的高活性。本研究为胶体壳聚糖制备 COSs 提供了一种冷活性和高效的壳聚糖酶，并为其应用提供了思路。
