Label-free quantitative proteomic analysis reveals muscle contraction and metabolism proteins linked to ultimate pH in bovine skeletal muscle.

The purpose of this research was to investigate the causes and consequences of pHu variations in beef cattle. A group of 176 Nellore beef cattle was evaluated and classified into two different pHu groups: High (≥6.0, N = 17) and Normal (<5.8, N = 159). Plasma concentrations of cortisol and adrenocorticotropic hormone, lactate and glycogen muscular content, meat color, shear force and Longissimus thoracis muscle proteomic profile were evaluated and compared between pHu groups. Muscle glycogen content, meat color and shear force statistically differed between pHu groups. Label-free quantitative proteomic analysis revealed ten differentially abundant proteins between pHu groups, involved in metabolic processes and muscle contraction, which also were significantly correlated with pHu. Thirty-six and 31 proteins were exclusively present in Normal and High pHu group, respectively, which were related to TCA cycle, cortisol production, calcium regulation, and antioxidant function. The MYH7, UGP2, H2AFJ and VDAC3 were identified as potential indicators of pHu variations. CALM and NNT appeared to be interesting proteins to understand the metabolic pathways behind pHu. Data are available via ProteomeXchange with identifier PXD009320.