摘要：

利用蛋白质组学的方法对娟犏牛奶与牦牛奶乳清和乳脂球膜(MFGM)相同蛋白进行分析,而娟犏牛产奶量高于牦牛,若娟犏牛奶的功能与牦牛奶相近,将提高当地牧民的经济水平。通过离心法分离乳清与乳脂,分别提取蛋白;通过串联质量标签(TMT)技术,进行蛋白质定性与定量分析得到相同蛋白;对相同蛋白进行GO功能注释、KEGG代谢通路、蛋白互作等生物信息学分析。结果表明,利用标记定量蛋白质组学技术在娟犏牛奶与牦牛奶中共鉴定到651种乳清蛋白和990种MFGM蛋白,筛选出298种乳清相同蛋白,283种MFGM相同蛋白。GO注释分析发现,鉴定的娟犏牛奶与牦牛奶乳清相同蛋白主要参与的生物过程是内肽酶活性的负调控、免疫应答和免疫球蛋白产生,MFGM相同蛋白参与的生物过程主要是内肽酶活性的负调控和补体激活,经典途径乳清与MFGM相同蛋白定位的细胞成分主要是胞外间隙和胞外区,参与的分子功能主要是三磷酸鸟苷(GTP)酶活性、GTP结合。KEGG富集分析发现,娟犏牛奶与牦牛奶乳清与MFGM相同蛋白主要富集的途径包括补体和凝血级联反应、吞噬体和内质网中的蛋白加工。娟犏牛奶和牦牛奶中丰度较高的蛋白显示出其在免疫和促进营养吸收等方面表现优异,然而,娟犏牛产奶量高于牦牛,这将增加当地牧民的经济收入,也为人们提供更多有价值的高原奶制品。

关键词: 娟犏牛奶, 牦牛奶, 乳清蛋白, 乳脂球膜蛋白, 蛋白质组学

Abstract:

To analyze the same protein of whey and milk fat globule membrane (MFGM)of jersey yak crossbreeds milk and yak milk by proteomics method. The milk yield of jersey yak crossbreeds was higher than that of yak. If the function of jersey yak crossbreeds milk is like that of yak milk,it will improve the economic level of local herdsmen. Whey and milk fat were separated by centrifugation,and proteins were extracted respectively. The same protein was obtained by qualitative and quantitative analysis of protein by tandem mass tag (TMT)technique. GO functional annotation,KEGG metabolic pathway,protein interaction and other bioinformatics analysis were performed on the same protein. Result analysis indicated that 651 whey proteins and 990 MFGM proteins were identified in the peak lactation period of jersey yak crossbreeds milk and yak milk by label quantitative proteomics,and 298 whey proteins and 283 MFGM proteins were screened. GO annotation analysis showed that the same proteins of jersey yak crossbreeds milk and yak milk whey were mainly involved in the negative regulation of endopeptidase activity,immune response and immunoglobulin production. The same proteins of MFGM were mainly involved in the negative regulation of endopeptidase activity and complement activation. The cell components of the same proteins of whey and MFGM in the classical pathway were mainly extracellular space and extracellular region. The molecular functions involved were mainly guanosine 5'-triphosphate (GTP)enzyme activity and GTP binding. KEGG enrichment analysis showed that the main enrichment pathways of the same proteins in jersey yak crossbreeds milk and yak milk whey and MFGM included complement and coagulation cascades,phage and protein processing in endoplasmic reticulum. During the peak lactation period,the proteins with higher abundance in the milk of jersey yak crossbreeds and yak showed excellent performance in immunity and promoting nutrient absorption. However,the milk yield of jersey yak crossbreeds was higher than that of yak,which would increase the economic income of local herdsmen and provide more valuable plateau dairy products for people.

Key words: Jersey yak crossbreeds milk, Yak milk, Whey protein, Milk fat globule membrane protein, Proteomics