Quantitative phosphoproteomic analysis of ovine muscle with different postmortem glycolytic rates.

Phosphorylation regulates protein structure, function, cell signaling and enzyme activities within cells. Postmortem changes of muscle to meat are partially determined by the structure, function and enzyme activities of proteins. To further understand the mechanisms regulating postmortem changes, ovine muscles with different glycolytic rates were subjected to quantitative phosphoproteomic analysis. Totally 116 unique phosphopeptides matched to 99 phosphoproteins were detected to be different in abundance among the fast, moderate and slow glycolytic rate muscles. Of which, 24 phosphoproteins clustered into glycolysis and muscle contraction were selected after bioinformatics analysis. Quantitative analysis showed that phosphorylation of pyruvate kinase, phosphoglucomutase 1, enolase and fructose-bisphosphate aldolase was correlated with glycolytic rate early postmortem. In addition, some myofibrillar proteins were detected to be differentially phosphorylated. In summary, this study revealed that protein phosphorylation at early postmortem may indirectly affect the glycolysis pathway through the regulation of proteins involved in glycolysis and muscle contraction.