Key Laboratory of Marine Drugs, Ministry of Education, Shandong Provincial Key Laboratory of Glycoscience and Glycoengineering, School of Medicine and Pharmacy, Ocean University of China, Qingdao 266003, China; Laboratory for Marine Drugs and Bioproducts of Qingdao National Laboratory for Marine Science and Technology, Qingdao 266237, China.
Key Laboratory of Marine Drugs, Ministry of Education, Shandong Provincial Key Laboratory of Glycoscience and Glycoengineering, School of Medicine and Pharmacy, Ocean University of China, Qingdao 266003, China; Laboratory for Marine Drugs and Bioproducts of Qingdao National Laboratory for Marine Science and Technology, Qingdao 266237, China.
Int J Biol Macromol. 2020 Dec 15;165(Pt A):1211-1218. doi: 10.1016/j.ijbiomac.2020.10.011. Epub 2020 Oct 7.
Hyaluronic acid (HA) is an anionic linear polysaccharide abundantly distributed in the extracellular matrix of mammalian connective, growing, and tumor tissues. Hyaluronidase is used as an important drug diffusion promoter and a tool enzyme to produce HA oligosaccharides. However, there is no thermostable hyaluronidase suitable for application to date. In this study, a thermophilic hyaluronate lyase, TcHly8C, from Thermasporomyces composti DSM22891 was expressed in Escherichia coli. The recombinant TcHly8C was most active at 70 °C, and it retained about 30% of initial activity after incubation at 60 °C for 28 days. The half-lives of TcHly8C at 60 °C and 70 °C were 16.1 d and 2.3 h, respectively. The optimum pH of TcHly8C is 5.93, and it was stable at pH 6.15-10.90. The presence of Mg could enhance its enzymatic activity significantly. K, k, and k/K of TcHly8C towards HA were 3.69 mg∙ml, 17.82 s, and 4.82 ml∙mg∙s, respectively. TcHly8C degraded HA in an exolytic mode, and the end product was unsaturated HA disaccharide (ΔUA-GlcNAc). Overall, our results show that TcHly8C is the first reported PL8 exo-type hyaluronate lyase with high thermostability, which provides a potential enzyme used in medicine and production of HA oligosaccharides.
透明质酸（HA）是一种广泛分布于哺乳动物结缔组织、生长组织和肿瘤组织细胞外基质中的阴离子线性多糖。透明质酸酶被用作重要的药物扩散促进剂和产生 HA 寡糖的工具酶。然而，目前还没有适合应用的耐热透明质酸酶。本研究在大肠杆菌中表达了来自 Thermasporomyces composti DSM22891 的嗜热透明质酸裂解酶 TcHly8C。重组 TcHly8C 在 70°C时最活跃，在 60°C孵育 28 天后仍保留约 30%的初始活性。TcHly8C 在 60°C和 70°C时的半衰期分别为 16.1 天和 2.3 小时。TcHly8C 的最适 pH 为 5.93，在 pH 6.15-10.90 范围内稳定。Mg 的存在可显著增强其酶活性。TcHly8C 对 HA 的 K、k 和 k/K 分别为 3.69mg·ml、17.82s 和 4.82ml·mg·s。TcHly8C 以外切方式降解 HA，末端产物为不饱和 HA 二糖（ΔUA-GlcNAc）。总之，我们的研究结果表明，TcHly8C 是首个报道的具有高热稳定性的 PL8 外切型透明质酸裂解酶，为医学和 HA 寡糖生产提供了一种潜在的酶。
