Effects of protein phosphorylation on glycolysis through the regulation of enzyme activity in ovine muscle

To verify the effect of protein phosphorylation on glycolysis and elucidate the regulatory mechanism from the perspective of enzyme activity, ovine muscle was treated with a kinase inhibitor, dimethyl sulfoxide, or a phosphatase inhibitor and the activities of glycogen phosphorylase, pyruvate kinase and phosphofructokinase were determined. The protein phosphorylation level was significantly different after incubation of muscle with kinase or phosphatase inhibitors. The pH value and lactate content revealed that a high phosphorylation level was the reason for the fast glycolysis. The glycogen phosphorylase, pyruvate kinase and phosphofructokinase activities were significantly higher in the phosphatase inhibitor group than in the other two groups (p < 0.05). Therefore, protein phosphorylation is involved in activating these three enzymes. In summary, protein phosphorylation plays a role in post-mortem glycolysis through the regulation of enzyme activity in ovine muscle.