来源于Reinekea thalattae的褐藻胶裂解酶酶学性质研究

Enzymatic Characterization of an Alginate Lyase from Reinekea thalattae

摘要:

褐藻胶裂解酶可将褐藻胶有效降解为褐藻寡糖（alginate oligosaccharides, AOS），AOS具有良好的物理特性和生理功能，在食品、化妆品和医药等领域有着广泛应用。为高效制备AOS，筛选并鉴定了一种来自Reinekea thalattae的PL-7家族新型褐藻胶裂解酶Reth-aly，将Reth-aly的编码基因克隆并在大肠杆菌BL21中高效表达。在pH 7.5（Tris-HCl缓冲液）、35 ℃、600 mmol/L NaCl的条件下，Reth-aly表现出最高的催化活性。以海藻酸钠为底物，其催化活性可达765.7 U/mg，降解产物包含聚合度（degree of polymerization, DP） 2~4的AOS。与其他PL-7家族褐藻胶裂解酶相比，其在35 ℃下的半衰期为5.4 h，具有良好的稳定性。Reth-aly在高盐环境中表现出良好的催化活性，在AOS生物生产中具有良好的应用前景。

Abstract:

Alginate lyases could effectively degrade alginates into alginate oligosaccharides (AOS). AOS have good physical characteristics and excellent physiological functions, and are widely applied in the fields of food, cosmetics, and pharmaceuticals. To efficiently prepare AOS, a novel alginate lyase belonging to the PL-7 family and derived from Reinekea thalattae was screened and identified, designated as Reth-aly. The encoding gene of Reth-aly was cloned and overexpressed in Escherichia coli BL21. Under conditions of pH 7.5 (Tris-HCl buffer), 35 ℃ and 600 mmol/L NaCl, Reth-aly demonstrated its highest catalytic activity. With sodium alginate as the substrate, its catalytic activity reached 765.7 U/mg. Degradation products included AOS with a degree of polymerization (DP) of 2~4. Compared with other PL-7 family alginate lyases, it showed good stability with a half-life of 5.4 h at 35 ℃. Reth-aly showed robust catalytic activity in high-salt environments, indicating promising application prospects in AOS bioproduction.