Protein Phosphorylation Induced by Pyruvate Kinase M2 Inhibited Myofibrillar Protein Degradation in Post-Mortem...

Area of Science:

• Biochemistry
• Food Science
• Enzymology

Background:

• Myofibrillar protein degradation influences meat tenderness.
• Protein phosphorylation is a key regulatory mechanism in this process.
• Pyruvate kinase M2 (PKM2), a glycolytic enzyme, also functions as a protein kinase.

Purpose of the Study:

• To investigate the relationship between PKM2-induced phosphorylation and myofibrillar protein degradation.
• To determine the effect of temperature on PKM2's phosphorylation activity.
• To elucidate PKM2's role in meat tenderization pathways.

Main Methods:

• Incubation of myofibrillar proteins with PKM2 at varying temperatures (4, 25, and 37 °C).
• Measurement of global myofibrillar protein phosphorylation levels.
• Assessment of desmin and actin degradation following PKM2 treatment.

Main Results:

• PKM2 significantly increased myofibrillar protein phosphorylation in a temperature-dependent manner.
• Optimal phosphorylation and inhibition of protein degradation occurred at 37 °C.
• PKM2-mediated phosphorylation of desmin and actin inhibited their degradation at 37 °C.

Conclusions:

• PKM2-catalyzed phosphorylation of myofibrillar proteins inhibits protein degradation.
• This suggests a novel pathway for meat tenderization involving glycolytic enzyme regulation.
• Understanding PKM2's role can inform strategies for improving meat quality.