Effect of oxygen free radicals on myosin in muscle fibres.
Experiments were performed on glycerol-extracted muscle fibres prepared from psoas muscle of rabbit in the presence of hydroxyl free radical generating system. Short irradiation of spin-labelled muscle fibres by UV light showed the interaction of probe molecules with oxygen free radicals. The intensity of the EPR signal from maleimide or isothiocyanate spin labels attached to the essential thiol groups decreased following irradiation. Oxygen free radicals affected the rate constant of the transition AM.ADP.Vi-->AM.ADP in the ATP hydrolysis cycle. It was found that the essential -SH groups of myosin were involved in the oxidation of sulphydryls by Ce(IV). Ce(IV) complexed to nitrilotriacetic acid in the presence of spin trap produced long-lived free radicals located partly on SH-1 sulphydryls.
Könczöl
F
F
Institute of Forensic Medicine, University Medical School, Pécs, Hungary.
Lorinczy
D
D
Belagyi
J
J
D000244:Adenosine Diphosphate / Q000378:metabolism; D000255:Adenosine Triphosphate / Q000378:metabolism; D000818:Animals; D002586:Cesium / Q000494:pharmacology; D003545:Cysteine / Q000737:chemistry; D004578:Electron Spin Resonance Spectroscopy; D006868:Hydrolysis; D017665:Hydroxyl Radical / Q000378:metabolism*; D066298:In Vitro Techniques; D018485:Muscle Fibers, Skeletal / Q000378:metabolism* / Q000528:radiation effects; D009218:Myosins / Q000737:chemistry / Q000378:metabolism* / Q000528:radiation effects; D016877:Oxidants / Q000494:pharmacology; D010084:Oxidation-Reduction; D016658:Psoas Muscles / Q000378:metabolism / Q000528:radiation effects; D011817:Rabbits; D013113:Spin Labels; D013438:Sulfhydryl Compounds / Q000378:metabolism; D014466:Ultraviolet Rays; D014638:Vanadates / Q000494:pharmacology
D016877:Oxidants; D013113:Spin Labels; D013438:Sulfhydryl Compounds; D002586:Cesium; D017665:Hydroxyl Radical; D014638:Vanadates; D000244:Adenosine Diphosphate; D000255:Adenosine Triphosphate; D009218:Myosins; D003545:Cysteine