Koššuthová Alžbeta, Antošová Monika, Bauerová-Hlinková Vladena, Bauer Jacob A, Polakovič Milan
Department of Chemical and Biochemical Engineering, Institute of Chemical and Environmental Engineering, Faculty of Chemical and Food Technology, Slovak University of Technology, Radlinského 9, 812 37 Bratislava, Slovakia.
Department of Biochemistry and Structural Biology, Institute of Molecular Biology, Slovak Academy of Sciences, Dúbravská Cesta 21, 845 51 Bratislava, Slovakia.
Biomolecules. 2025 May 31;15(6):801. doi: 10.3390/biom15060801.
β-Galactosidase, a glycoside hydrolase enzyme, also possesses glycosyl transferase activity and can glycosylate various aglycones, including tyrosol, a phenylethanoid with antioxidant and health-promoting effects. This study examines the effect of lactose, tyrosol and deep eutectic solvents (DESs) as co-solvents on the stability and activity of β-galactosidase during the enzymatic synthesis of tyrosol β-d-galactoside (TG). The enzyme's thermal stability was assessed using nanoDSF and circular dichroism spectroscopy, while the enzyme's activity and specificity toward different glycosyl acceptors were investigated using the initial rate method. The effects of tyrosol and DESs on tyrosol galactoside synthesis over a 6 h period were also studied. Lactose and glycerol were found to stabilize the enzyme. Among the DESs tested, those containing betaine showed the highest stabilizing effect. The presence of DESs not only affected the overall enzyme activity but also changed the enzyme specificity, most frequently in favor of lactose hydrolysis. Components of DESs containing alcohol groups (polyols) also acted as transglycosylation acceptors. However, both glycerol and tyrosol were found to inhibit overall enzyme activity and TG synthesis. Overall, our findings provide new and valuable insights into the influence of reaction conditions on the stability and specificity of β-galactosidase.
β-半乳糖苷酶是一种糖苷水解酶，也具有糖基转移酶活性，能够使多种苷元糖基化，包括酪醇，一种具有抗氧化和促进健康作用的苯乙醇类化合物。本研究考察了乳糖、酪醇和作为共溶剂的低共熔溶剂（DESs）对酪醇β-D-半乳糖苷（TG）酶促合成过程中β-半乳糖苷酶稳定性和活性的影响。使用纳米差示扫描荧光法和圆二色光谱法评估了该酶的热稳定性，同时采用初速率法研究了该酶对不同糖基受体的活性和特异性。还研究了酪醇和DESs在6小时内对酪醇半乳糖苷合成的影响。发现乳糖和甘油可使该酶稳定。在所测试的DESs中，含有甜菜碱的DESs表现出最高的稳定效果。DESs的存在不仅影响了酶的整体活性，还改变了酶的特异性，最常见的是有利于乳糖水解。含有醇基（多元醇）的DESs成分也可作为转糖基化受体。然而，发现甘油和酪醇均会抑制酶的整体活性和TG合成。总体而言，我们的研究结果为反应条件对β-半乳糖苷酶稳定性和特异性的影响提供了新的有价值的见解。
