Identification of restricting factors that inhibit swelling of oxidized myofibrils during brine irrigation.
Porcine longissimus myofibrils were exposed to a hydroxyl radical-oxidizing system (10 microM FeCl3, 100 microM ascorbic acid, 1 mM H2O2) at pH 6.2 for 1-12 h. Chemical analyses (sulfhydryls, disulfide bonds, carbonyls) indicated mild protein oxidation along with almost 40% loss of protein extractability in low-ionic-strength brines (<or=0.4 M NaCl, 10 mM pyrophosphate, pH 6.2). Upon graded brine irrigation (0.2-->0.6 M NaCl) with pyrophosphate, the swelling of myofibrils and the dissolution of the A-band of oxidized myofibrils were less pronounced than those of nonoxidized. This restriction of myofibril swelling, caused largely by disulfide cross-linkages formed between oxidized myosin tails, was positioned on the transversely expansible thick filaments, reflecting a significant role and susceptibility of intra- as well as intermyofilamental structures.
Liu
Zelong
Z
State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi 214122, China.
Xiong
Youling L
YL
Chen
Jie
J
D000818:Animals; D003432:Cross-Linking Reagents; D004220:Disulfides / Q000737:chemistry; D017665:Hydroxyl Radical / Q000737:chemistry; D009124:Muscle Proteins / Q000032:analysis; D009210:Myofibrils / Q000737:chemistry / Q000187:drug effects* / Q000648:ultrastructure; D009218:Myosins / Q000737:chemistry; D009994:Osmolar Concentration; D010084:Oxidation-Reduction; D012492:Salts / Q000008:administration & dosage*; D013552:Swine; D014867:Water / Q000378:metabolism
D003432:Cross-Linking Reagents; D004220:Disulfides; D009124:Muscle Proteins; D012492:Salts; C017082:brine; D014867:Water; D017665:Hydroxyl Radical; D009218:Myosins