Instability of SDS-denatured proteins prepared from musle myofibrils

Area of Science:

• Biochemistry
• Muscle Physiology

Background:

• Myofibrils are essential contractile units in muscle tissue.
• Solubilization of myofibrils is a common technique in biochemical analysis.
• Protein degradation can complicate experimental results.

Purpose of the Study:

• To investigate protein degradation in solubilized myofibrils.
• To identify the cause of artifactual protein bands in muscle samples.
• To propose methods for preventing sample degradation.

Main Methods:

• Solubilization of myofibrils using sodium dodecyl sulfate.
• Incubation of samples at room temperature and refrigerated conditions.
• Analysis of protein degradation using gel electrophoresis.

Main Results:

• Solubilized myofibrils showed signs of proteolysis upon warming or prolonged cold storage.
• Additional protein bands observed were attributed to endogenous muscle proteases.
• Artifactual degradation occurred during overnight warming or several days of cold storage.

Conclusions:

• Indigenous muscle proteases can degrade solubilized myofibrils, creating artifacts.
• Modified sample handling protocols are necessary to avoid protease-induced artifacts.
• The role of these proteases in meat tenderness warrants further investigation.