Proteomic analysis of differentially expressed whey proteins in Guanzhong goat milk and Holstein cow milk by iTRAQ coupled with liquid chromatography-tandem mass spectrometry

Abstract

Guanzhong goat and Holstein cow milk are the major milks supplied in China. Whey proteins play an important role in immune defense for newborn mammals. This study aimed to analyze the differentially expressed whey proteins of Guanzhong goat milk and Holstein cow milk by using isobaric tags for relative and absolute quantitation (iTRAQ)-based proteomics techniques. A total of 165 whey proteins were quantified, 114 of which differed significantly in abundance in goat and cow milks. According to the "up_keywords," in the online DAVID tool (https: / / david .ncifcrf .gov/ home .jsp), 75% of these differentially expressed whey proteins were related to the category of "signal." Gene Ontology analyses classified these differentially expressed proteins into biological processes, cellular components, and molecular functions. The most common biological process was response to stress, the most common cellular component was related to extracellular region, and the most prevalent molecular function was binding. Kyoto Encyclopedia of Genes and Genomes pathway analyses showed that these proteins were mainly involved in the complement and coagulation cascade pathways. The results improve our understanding of the different biological properties of whey proteins in goat and cow milks.

Identification markers of goat milk adulterated with bovine milk based on proteomics and metabolomics

“…Serpin A3–1, an inhibitor of the serine proteases elastase and trypsin, has been detected in bovine milk. A previous study using an iTRAQ-LC-MS quantification–based proteomics approach showed that serpin A3–1 abundance was significantly higher in bovine milk than in goat milk ( Sun, Wang, Sun, & Guo, 2020 ). In the current study, serpin A3–1 was present in goat milk adulterated with bovine milk and could be used to assess such adulteration of goat milk samples.…”