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[Structural and functional changes in myosin from rat skeletal muscles during postmortem autolysis]
Voprosy Meditsinskoi Khimii
|November 1, 1988
Summary
Postmortem autolysis in rat skeletal muscle affects myosin's enzymatic activity, decreasing Ca2+-ATPase function within 3 hours. While myosin structure remains intact initially, heavy chain degradation occurs later, impacting enzyme function.
Area of Science:
- Biochemistry
- Muscle Physiology
- Proteomics
Background:
- Myosin is a crucial protein in muscle contraction.
- Postmortem changes in muscle tissue, known as autolysis, can affect protein structure and function.
- Understanding these changes is vital for studying muscle biology and postmortem processes.
Purpose of the Study:
- To investigate the structural and enzymatic alterations of myosin during postmortem autolysis in rat skeletal muscle.
- To determine the timeline of myosin degradation and functional loss after death.
Main Methods:
- Studied myosin from rat skeletal muscles at various postmortem intervals.
- Assessed Ca2+-ATPase activity to measure enzymatic function.
- Utilized gel filtration in 8 M urea and SDS-PAGE for structural analysis.
- Observed the phenomenon of substrate inhibition.
Main Results:
- Ca2+-ATPase activity of myosin decreased significantly within 3 hours postmortem.
- Myosin structure, analyzed by gel filtration and SDS-PAGE, remained largely intact during the initial 3 hours.
- Substrate inhibition was observed in both native and isolated myosin.
- Marked decrease in enzymatic activity and degradation of myosin heavy chains occurred by 12 and 24 hours postmortem.
Conclusions:
- Myosin's enzymatic function, specifically Ca2+-ATPase activity, is sensitive to early postmortem autolysis.
- Myosin's structural integrity is maintained longer than its enzymatic activity during early autolysis.
- Later stages of autolysis involve significant degradation of myosin heavy chains, leading to profound loss of function.