Phosphorylation promoted the glycolytic rate in postmortem meat by tightening the structure of glycogen phosphorylase

Abstract The activity and structural variation of glycogen phosphorylase (GP) at different phosphorylation levels during incubation at 4 °C were explored in this study. The GP was assigned into four treatments to obtain high/low phosphorylation levels, which were (1) treated with glycogen phosphorylase kinase (Phk) to obtain high phosphorylation level, (2) treated with protein kinase A to obtain high phosphorylation level, (3) treated with alkaline phosphatase to obtain low phosphorylation level, and (4) control. Compared with the control group, the content of α-helix and β-sheet increased and the secondary structure of GP changed from disorder to order after phosphorylation. The activity of GP was increased and its structure was more tightly in the Phk group than that in the control group. The phosphorylation at Ser277, Ser430, Ser809, Thr304, Tyr298, and Tyr525 resulted in tighter spatial structure. In conclusion, phosphorylation of GP enhanced its catalytic activity by making the secondary and spatial structure more orderly, which is of great significance for controlling meat quality by regulating glycolysis.