title: Oxidation desensitizes actomyosin to magnesium pyrophosphate-induced dissociation.
abstract: This study aimed to establish the influence of protein oxidation on the ability of magnesium pyrophosphate (PP) to dissociate actomyosin. Actomyosin isolated from pork muscle then suspended in 0.1M NaCl at pH 6.2 was oxidatively stressed with 10 μM FeCl3/0.1mM ascorbate/1mM H2O2 for 6 or 12h at 4°C. Protein oxidation was evidenced by the loss of myosin and actin, the concomitant formation of disulphide-cross-linked polymers, and elevated myosin ATPase activity. The intrinsic viscosity of oxidized actomyosin had a weaker response to PP-Mg(2+) than that of non-oxidized actomyosin, indicating the suppression of actomyosin dissociation. Moreover, oxidized actomyosin solutions were devoid of small particles (<10nm) and the stressed actomyosin exhibited weaker binding of PP-Mg(2+) than non-oxidized, which further suggested a reduced myosin-PP interaction and subsequent dissociation of the actomyosin complexes.
authors.affiliation: State Key Laboratory of Food Science and Technology, and School of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu 214122, China.
authors.forename: Zelong
authors.initials: Z
authors.lastname: Liu
authors.forename: Youling L
authors.initials: YL
authors.lastname: Xiong
mesh_terms: D000205:Actomyosin / Q000737:chemistry*; D000818:Animals; D011756:Diphosphates / Q000494:pharmacology*; D005503:Food Additives / Q000494:pharmacology*; D005511:Food Handling; D017616:Magnesium Compounds / Q000494:pharmacology*; D008460:Meat / Q000032:analysis*; D018482:Muscle, Skeletal / Q000737:chemistry*; D010084:Oxidation-Reduction / Q000187:drug effects; D013552:Swine; D014783:Viscosity / Q000187:drug effects
chemical_list: D011756:Diphosphates; D005503:Food Additives; D017616:Magnesium Compounds; D000205:Actomyosin; C034732:magnesium pyrophosphate