State Key Laboratory of Food Science and Technology, Nanchang University, Nanchang, China.
School of Food Science and Technology, NanchangUniversity, Nanchang, China.
J Food Biochem. 2020 Sep;44(9):e13340. doi: 10.1111/jfbc.13340. Epub 2020 Jul 15.
Bovine α-lactalbumin (α-LA) is recognized as a major milk allergen. Generally, α-LA in the natural state combines with a calcium ion, however, some studies have shown that calcium ions can binding the other metal binding sites in α-LA as well. In our study, the optimal condition of calcium ion binding to α-LA and the change of structure and allergenicity were explored. By optimizing the conditions, the maximum calcium binding amounts of apo-α-LA were obtained in a ratio of 1:4. The structure of α-LA after removal of calcium obviously changed by the spectroscopic detection. For the digestive stability, there was no obvious change in three forms of α-LA. While the allergenic properties were characterized by IgG/IgE inhibition ELISA and the human basophil KU812 degranulation assay. The results showed that IgG and IgE binding decreased, and the degranulation capacity of basophils weakened. Based on these results, calcium binding to apo-α-LA can reduce the potential allergenic properties. PRACTICAL APPLICATIONS: By optimizing the conditions, bovine apo-α-LA can obtain the most calcium binding amount. And calcium binding to apo-α-LA can reduce the potential allergenic properties. Compared with α-LA in the natural state, calcium binding to α-LA not only can reduce the allergenic properties, but also play a role in calcium supplementation. It might be used to guide the development of hypoallergenic α-LA and provide a method to reduce the potential allergenic properties of α-LA.
牛α-乳白蛋白（α-LA）被认为是一种主要的牛奶过敏原。通常，天然状态下的α-LA 与钙离子结合，但有研究表明，钙离子也可以结合α-LA 中的其他金属结合位点。在本研究中，我们探索了钙离子与α-LA 结合的最佳条件以及结构和变应原性的变化。通过优化条件，获得了无钙α-LA 的最大钙结合量，其比例为 1:4。光谱检测表明，去除钙离子后α-LA 的结构明显发生变化。对于消化稳定性，三种形式的α-LA 均无明显变化。而过敏原特性则通过 IgG/IgE 抑制 ELISA 和人嗜碱性粒细胞 KU812 脱颗粒测定来表征。结果表明，IgG 和 IgE 结合减少，嗜碱性粒细胞的脱颗粒能力减弱。基于这些结果，钙与脱辅基α-LA 的结合可以降低潜在的变应原性。实际应用：通过优化条件，牛脱辅基α-LA 可以获得最大的钙结合量。而且，钙与脱辅基α-LA 的结合可以降低潜在的变应原性。与天然状态下的α-LA 相比，钙与α-LA 的结合不仅可以降低变应原性，还可以起到钙补充的作用。它可能用于指导低变应原性α-LA 的开发，并提供一种降低α-LA 潜在变应原性的方法。
