Four high-molecular-weight protein fractions of milk fat globule membrane (MFGM) were isolated from bovine milk. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), MALDI-TOF/TOF™ and Liquid chromatography electrospray ionization–tandem mass spectrometry (LC-ESI-MS/MS) were used to measure the molecular sizes of the MFGM. Fourier transform infrared spectroscopy (FT-IR) and circular dichroism (CD) were performed to determine the conformations of the MFGM. The results showed that the main protein (98.33%) in MFGM protein fraction 2 was Milk fat globule epidermal growth factor-VIII (MFG-E8), with a molecular weight of 47.82 kDa. The secondary structural component measurements showed that the MFG-E8 consisted of 5% helix, 70% sheet and 25% random coil, and the results matched well with the prediction by SSPro 5.1 bioinformatic analysis. The thermograms analysis revealed that Td and△H of MFG-E8 were 60.50°Cand 132.29 kJ/mol. The in vitro digestibility of MFG-E8 showed that it can be enzymatically hydrolyzed in the stomach and relatively stable in the intestinal fluid. The in vitro C₂C₁₂ and Caco2 cell activity tests indicated that MFG-E8 promoted the proliferation of C₂C₁₂ myoblast cells without cytotoxicity. The biological functional properties of MFG-E8 may be related to the fact that MFG-E8 possesses a high level of β-sheet structure. Our results suggested that MFG-E8 possesses broad prospects not only for use in functional food products but also as a source of natural anti-sarcopenia drugs.

从牛乳中分离出四个乳脂球膜（MFGM）的高分子量蛋白质级分。十二烷基硫酸钠-聚丙烯酰胺凝胶电泳（SDS-PAGE），MALDI-TOF / TOF™和液相色谱电喷雾电离串联质谱（LC-ESI-MS / MS）用于测量MFGM的分子大小。进行傅立叶变换红外光谱（FT-IR）和圆二色性（CD）以确定MFGM的构象。结果表明，MFGM蛋白组分2中的主要蛋白（98.33％）是乳脂球表皮生长因子-VIII（MFG-E8），分子量为47.82 kDa。二次结构成分测量表明，MFG-E8由5％螺旋，70％薄片和25％随机线圈组成，结果与SSPro 5的预测非常吻合。1生物信息学分析。热分析图显示MFG-E8的Td和△H为60.50°C和132.29 kJ / mol。在体外MFG-E8的消化率表明，它可在胃中通过酶法水解，并在肠液相对稳定。在体外c ^ ₂ Ç ₁₂和的Caco2细胞活性试验表明，MFG-E8促进C的扩散₂ Ç ₁₂成肌细胞无细胞毒性。MFG-E8的生物学功能特性可能与MFG-E8具有高水平的β-折叠结构的事实有关。我们的结果表明，MFG-E8不仅在功能性食品中具有广阔的应用前景，而且还可以作为天然的抗肌肉减少症药物的来源。