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Oxidation desensitizes actomyosin to magnesium pyrophosphate-induced dissociation

Zelong Liu1, Youling L Xiong

  • 1State Key Laboratory of Food Science and Technology, and School of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu 214122, China.

Food Chemistry
|June 25, 2013
PubMed

Insights

Protein oxidation impairs magnesium pyrophosphate's ability to break down actomyosin. This research shows oxidized actomyosin has reduced binding and dissociation, impacting muscle function.

Area of Science:

  • Biochemistry
  • Muscle Physiology
  • Protein Chemistry

Background:

  • Actomyosin is crucial for muscle contraction.
  • Protein oxidation can alter protein structure and function.
  • Magnesium pyrophosphate (PP) plays a role in actomyosin dissociation.

Purpose of the Study:

  • To investigate how protein oxidation affects magnesium pyrophosphate's ability to dissociate actomyosin.
  • To understand the molecular mechanisms underlying this interaction.

Main Methods:

  • Actomyosin was isolated from pork muscle.
  • Oxidative stress was induced using FeCl3/ascorbate/H2O2.
  • Changes in protein structure, ATPase activity, and particle size were analyzed.
  • The interaction between actomyosin and magnesium pyrophosphate was measured using intrinsic viscosity and binding assays.

Main Results:

  • Oxidative stress led to protein loss, polymer formation, and increased myosin ATPase activity.
  • Oxidized actomyosin showed reduced dissociation in response to PP-Mg(2+).
  • Smaller particles were absent in oxidized actomyosin, and PP-Mg(2+) binding was weaker, indicating impaired myosin-PP interaction.

Conclusions:

  • Protein oxidation significantly suppresses the dissociation of actomyosin by magnesium pyrophosphate.
  • Oxidized actomyosin exhibits altered structural properties and reduced binding affinity for PP-Mg(2+).
  • These findings suggest that protein oxidation negatively impacts the actomyosin-PP interaction, affecting muscle function.

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