National "111" Center for Cellular Regulation and Molecular Pharmaceutics, Key Laboratory of Fermentation Engineering (Ministry of Education), Hubei University of Technology, Wuhan 430068, China; College of Bioengineering and Food, Hubei University of Technology, Wuhan 430068, China.
National "111" Center for Cellular Regulation and Molecular Pharmaceutics, Key Laboratory of Fermentation Engineering (Ministry of Education), Hubei University of Technology, Wuhan 430068, China; College of Bioengineering and Food, Hubei University of Technology, Wuhan 430068, China.
Food Chem. 2024 Aug 1;448:139082. doi: 10.1016/j.foodchem.2024.139082. Epub 2024 Mar 23.
β-galactosidase (lactase) is commercially important as a dietary supplement to alleviate the symptoms of lactose intolerance. This work investigated a unique activation of CMP (carboxymethylated (1 → 3)-β-d-glucan) on lactase and its mechanism by comparing it with carboxymethyl chitosan (CMCS), an inhibitor of lactase. The results illustrated that the secondary and tertiary structures of lactase were altered and its active sites exposed after complexation with CMP, and dissociation of lactase aggregates was also observed. These changes favored better accessibility of the substrate to the active sites of lactase, resulting in a maximum increase of 60.5 % in lactase activity. Furthermore, the hydrophobic and electrostatic interactions with lactase caused by the carboxymethyl group of CMP were shown to be crucial for its activation ability. Thus, the improvement of lactase activity and stability by CMP shown here is important for the development of new products in the food and pharmaceutical industries.
β-半乳糖苷酶（乳糖酶）作为一种膳食补充剂，具有重要的商业价值，可以缓解乳糖不耐受的症状。本研究通过与乳糖酶抑制剂羧甲基壳聚糖（CMCS）进行比较，研究了 CMP（羧甲基化（1→3）-β-葡聚糖）对乳糖酶的独特激活作用及其机制。结果表明，CMP 与乳糖酶结合后，改变了乳糖酶的二级和三级结构，暴露了其活性位点，并观察到乳糖酶聚集体的解离。这些变化有利于底物更好地进入乳糖酶的活性位点，从而使乳糖酶活性最大提高了 60.5%。此外，CMP 羧甲基引起的与乳糖酶的疏水和静电相互作用对于其激活能力至关重要。因此，CMP 对乳糖酶活性和稳定性的提高对食品和制药行业新产品的开发具有重要意义。
