人乳是婴幼儿生命初始阶段唯一能够摄入的食物，蛋白质是人乳中重要的营养成分，而牛乳作为代替人乳的常用原料已经被广泛的应用于婴幼儿食品中。本研究利用SDS-PAGE电泳和LC-MALDL-TOF蛋白组学方法将人乳与牛乳中乳脂肪球膜蛋白进行分离，能够发现人乳与牛乳脂肪球膜蛋白存在较大的差异。牛乳脂肪球膜中已鉴定出488种蛋白，人乳脂肪球膜中鉴定出的蛋白为1545种。牛乳脂肪球膜具有173种特异性蛋白，人乳脂肪球膜具有1230种特异性蛋白，在人乳与牛乳中存在315种同源蛋白。从蛋白质的GO（Gene Ontology）功能注释上来看，人乳脂肪球膜蛋白参与的生物过程有37%为代谢过程；具有的分子功能55%为结合作用；34%为参与细胞器构成。人乳脂肪球膜中有24种蛋白参与免疫相关的通路，主要为抗原加工和呈递。与牛乳相比，对人乳中乳脂肪球膜蛋白质在组成及功能上的研究，能够促进深入地了解人乳蛋白，并为以牛乳为原料的婴幼儿产品添加功能性蛋白提供参考。

Human milk is the sole food source in the initial stage of an infant’s life. Protein is an important nutrient in human milk, and cow’s milk has been widely used in infant formula as a raw material to replace human milk. In this study, sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) and liquid chromatography-matrix-assisted laser desorption/ionization-time of flight (LC-MALDI-TOF) proteomic methods were used to isolate and identify the milk fat globule membrane proteins (MFGPs) from human and bovine milk, and significant differences between the MFGPs in the two types of milk were found. The results showed that 488 and 1545 different protein species were identified in milk fat globule membranes of bovine and human milk, respectively. Among these proteins, there were 173 unique proteins in bovine milk fat globule membranes, 1230 unique proteins in human milk fat globule membranes, and 315 proteins found in both human and bovine milk. According to gene ontology (GO) annotations, 37% of biological processes involving human MFGPs were metabolic processes, 55% of molecular functions were for combination, and 34% of human MFGPs participated in constituting cell organelles. Twenty-four human MFGPs were involved in the immune related pathways, mainly for antigen processing and presentation. By comparing with bovine milk, studying the composition and functions of human MFGPs can improve our understanding of the proteins present in human milk, and provide a reference for adding functional proteins to infant formula products.

十二五农村领域国家科技计划课题(2013BAD18B03-02)