水牛和奶牛乳脂肪球膜蛋白组成和功能性的比较

Comparison of the protein compositions and functional properties for bovine and buffalo MFGMPs

为比较不同乳源的乳脂肪球膜蛋白(MFGMPs)蛋白质组成、含量和功能差异,用iTRAQ技术对水牛和奶牛MFGMPs进行分离、比较.采用Nano-HPLC-MS联合Q-Exactive的方法,对MFGMPs进行分离和鉴定,共鉴定出FDR≤0.01%的蛋白质424个,差异极显著蛋白146个,其中2倍(水牛/奶牛)上调蛋白20个,下调蛋白25个.水牛MFGMPs差异蛋白为磷酸钠溶质载体蛋白和γ-谷氨酰转肽酶,这两种蛋白具有载体和催化活性,为生物体的合成、代谢提供基本组分.奶牛MFGMPs差异蛋白为黄嘌呤氧化还原酶和嗜乳脂蛋白,这两种蛋白属于结合蛋白,具有抑制肿瘤细胞的功能特性.结果表明,奶牛和水牛MFGMPs中部分功能性蛋白在含量上存在一定的差异.

The iTRAQ techniques were used to separate and identify milk fat globule membrane proteins （ MFGMPs） from bovine and buffalo milk to compare the differences among composition, contents and functional properties of them. MFGMPs were separated and analyzed by Nano-HPLC tandem MS （ MS/MS） analysis coupled with Q-Exactive. The results showed that 424 proteins were identified （ FDR≤0. 01%） . The contents of 146 proteins were significantly different between MFGMPs bovine and buffalo in these identified proteins. Among these different proteins, there were 20 up regulated proteins and 25 down regulated proteins by two times （ buffalo/bovine） . The contents of sodium phosphate solute carrier protein and γ-glutamyl transpeptidase are significantly higher in buffalo MFGMPs than in bovine MFGMPs. The two proteins possess carriers and catalytic activities, and serve as the basic composition of biosynthesis and metabolism. The contents of xanthine oxidoreductase and butyrophilin are significantly higher in bovine MFGMPs than in buffalo MFGMPs. The two proteins, identified as binding protein, can inhibit the growth of tumor cell. The results showed that the significant differences of content existed in some functional protein between the MFGMPs of buffalo and bovine.