Abstract In order to study the tenderness mechanism of difference in different parts of Yak meat, the differentially expressed proteins (DEPs) and its correlation with quality of Yak meat were studied by TMT (Tandem Mass Tags, TMT) quantitative proteomic method. The results showed that 25, 40 and 34 DEPs were identified in JR/HGT, WJR/HGT and WJR/JR groups, respectively. Correlation analysis between DEPs and quality traits of yak meat showed that there were 12 DEPs with significant correlation were correlated closely with quality traits.The relative contents of the 11 DEPs were significantly different in different parts (p < 0.05).There are 8, 9 and 6 key DEPs in JR/HGT, WJR/HGT and WJR/JR groups, respectively.The expression of these DEPs were down-regulated and up-regulated in different parts, and was closely related to the cell growth and death, carbohydrate metabolism, amino acid metabolism, protein binding, motility activity and unfolded protein binding.The significant difference of the expression of these key proteins in different parts is the internal reason of the difference of quality traits among WJR, JR and HGT.This provide a reference for the study on the mechanism of difference in Yak meat.

Abstract Proteomics is a powerful tool to understand molecular connections between meat proteins and quality traits. In order to research the total proteome difference and molecular mechanisms related to quality traits in different parts of yak meat. This study was designed to investigate the differences in the proteomes of yak different muscles. In this paper, Tandem Mass Tags (TMT) coupled Liquid chromatography-tandem mass spectrometry (LC-MS/MS) to study the variations of proteome in different parts of yak after it is slaughtered. In total, 88 differentially expressed proteins (DEPs) were identified among striplon (WJR), slivsid (HGT) and chuck (JR). The quality analysis of DEPs showed heat shock proteins (HSPs) and structural proteins could be used as tenderness marker proteins for different parts of yak meat. Myosin and troponin-T may be flavour marker protein in yak meat. The bioinformatics analysis revealed that DEPs are involved in glycolysis, protein structure and phosphorylation. PPI analysis revealed thatmyosin, HSPs and metabolic enzymes may have the potential to be biological markers. This study highlights that the DEPs were responsible for meat quality different.