Recently, the meat science and nutrition research team, Institute of Food Science and Technology (IFST), Chinese Academy of Agricultural Sciences, revealed protein phosphorylation induced by pyruvate kinase M2 (PKM2) inhibited myofibrillar proteins degradation in postmortem muscle. The relevant research results were published in the top journal of food field “Journal of Agricultural and Food Chemistry” (JCR 1, IF: 6.1).

Tenderness is a key indicator to evaluate meat quality. The phosphorylation of myofibrillar protein is closely related to meat tenderness regulation. PKM2 is one of the important rate-limiting enzymes of glycolysis, and its glycolytic enzyme activity determines the development of meat quality. Previous studies have shown that PKM2 is not only a glycolytic enzyme (typical function), but also is a protein kinase (atypical function). However, whether PKM2 is involves in meat tenderness regulation through phosphorylating myofibrillar protein in postmortem meat is still unclear. In this study, PKM2 and myofibrillar protein were incubated at 4℃, 25℃ and 37℃ to investigate the effect of PKM2 on myofibrillar protein phosphorylation and degradation. The result showed that the function of PKM2 as a protein kinase was significantly affected by temperature. Within the 4℃~37℃ range, the higher temperature prompted a greater effect of PKM2 as a protein kinase on myofibrillar protein phosphorylation. In addition, the degradation of desmin and actin was inhibited after they were phosphorylated by PKM2 when incubated at 37℃. These results revealed the important functional property of PKM2 and provided a possible pathway of meat tenderization through glycolytic enzymes regulation.

Professor Xin Li is the corresponding author and the GSCAAS-LGg program PhD student Chi Ren is the first author. This study is financially supported by the Key Program (32030086) and General Program (32072144) from National Natural Science Foundation of China.

                                               

PKM2 regulates meat tenderness through phosphorylating myofibrillar protein phosphorylation

https://doi.org/10.1021/acs.jafc.3c03930