Lu Jing, Zhang Wenyuan, Ma Changlu, Pang Xiaoyang, Dai Ying, Zhu Tong, Liu Jinqi, Xing Lina, Zhang Shuwen, Lv Jiaping
Beijing Advanced Innovation Center for Food Nutrition and Human Health, Beijing Engineering and Technology Research Center of Food Additives, School of Food and Health, Beijing Technology and Business University, Beijing, China.
Institute of Food Science and Technology, Chinese Academy of Agricultural Science, Beijing, China.
Front Nutr. 2023 Jun 16;10:1161310. doi: 10.3389/fnut.2023.1161310. eCollection 2023.
Glycosylation is one of the essential post-translational modifications that influences the function of milk proteins.
In the present study, 998 proteins and 764 glycosylated sites from 402 glycoproteins were identified in human milk by TMT labeling proteomics. Compared to human milk proteins, the glycoproteins were mainly enriched in cell adhesion, proteolysis, and defense/immune process.
The abundance of 353 glycosylated sites and their 179 parent proteins was quantified. After normalization to their parent protein's abundance, 78 glycosylated sites in 56 glycoproteins and 10 glycosylated sites in 10 glycoproteins were significantly higher in colostrum and mature milk, respectively. These changed glycoproteins were mainly related to host defense. Intriguingly, one glycosylated site (Asp144) in IgA and two glycosylated sites (Asp38 and Asp1079) in tenascin are significantly upregulated even though their protein abundance was downregulated during lactation.
This study helps us figure out the critical glycosylated sites in proteins that might influence their biological function in an unbiased way.
糖基化是影响乳蛋白功能的重要翻译后修饰之一。
在本研究中，通过TMT标记蛋白质组学在人乳中鉴定出402种糖蛋白中的998种蛋白质和764个糖基化位点。与人乳蛋白相比，糖蛋白主要富集于细胞黏附、蛋白水解和防御/免疫过程。
对353个糖基化位点及其179个亲本蛋白的丰度进行了定量。将其与亲本蛋白的丰度进行归一化后，56种糖蛋白中的78个糖基化位点和10种糖蛋白中的10个糖基化位点在初乳和成熟乳中分别显著升高。这些变化的糖蛋白主要与宿主防御有关。有趣的是，尽管IgA中的一个糖基化位点（Asp144）和腱生蛋白中的两个糖基化位点（Asp38和Asp1079）在哺乳期其蛋白质丰度下调，但它们仍显著上调。
本研究有助于我们以无偏倚的方式找出可能影响蛋白质生物学功能的关键糖基化位点。
