AMP and IMP dissociate actomyosin into actin and myosin
Akihiro Okitani1, Naoki Ichinose, Miki Koza
1Department of Food Science and Technology, Nippon Veterinary and Life Science University, Musashino-shi, Tokyo, Japan.
Bioscience, Biotechnology, and Biochemistry
|August 8, 2008
Summary
Heating squid muscle causes actin to detach from myofibrils, with adenosine monophosphate (AMP) and inosine monophosphate (IMP) identified as key factors. These compounds also reverse muscle protein binding during cold storage, potentially resolving rigor mortis.
Area of Science:
- Muscle Physiology
- Biochemistry
- Food Science
Background:
- Actin liberation from myofibrils occurs when squid muscle is heated to 60°C.
- Understanding the molecular mechanisms behind postmortem muscle changes is crucial for food quality.
Purpose of the Study:
- To elucidate the factors responsible for actin liberation from squid muscle upon heating.
- To investigate the role of specific nucleotides in actomyosin dissociation and rigor mortis resolution.
Main Methods:
- Heating myofibrillar and sarcoplasmic fractions of squid muscle.
- Incubation of actomyosin from various animal skeletal muscles with ATP, AMP, and IMP at low temperatures.
Main Results:
- Actin liberation was observed when squid myofibrils were heated with sarcoplasmic fractions or specific nucleotides (ATP, AMP, IMP).
- Adenosine monophosphate (AMP) and inosine monophosphate (IMP) were identified as key factors inducing actin liberation.
- AMP and IMP were found to reversibly dissociate actomyosin in chicken, bovine, and porcine skeletal muscles at 0°C.
Conclusions:
- AMP and IMP are the primary factors responsible for actin liberation in heated muscle.
- These nucleotides also cause reversible dissociation of actomyosin during cold storage of skeletal muscle.
- AMP and IMP are potential contributors to the resolution of rigor mortis in muscle tissues.
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