[Modification of an enzymic system for Ca2+ transport in sarcoplasmic reticulum in lipid peroxidation. Change in the molecular organization of the lipoprotein Ca-ATPase complex].
Using ESR spectroscopy of spin probes and spin labelling, the effects of lipid peroxidation (LPO) on the molecular organization of Ca-ATPase from rabbit skeletal muscle sarcoplasmic reticulum membranes were studied. Accumulation of LPO products caused an increase of the hydrophobicity and a decrease of the mobility of the Ca-ATPase polypeptide chain fragment immediately proximal to the enzyme active site. Induction of LPO in the membranes resulted in a decrease of the thermal stability of the lipoprotein Ca-ATPase complex which occurred as a biphasic process. At temperatures of 36-38 degrees C this thermodenaturation consisted in a shift of the Ca-transport ability towards a lower temperature region corresponding to the shift in the low temperature break on the Arrhenius plots for parameter 2A'zz of the maleimide spin label. Within the temperature range of 49-52 degrees C an earlier LPO-induced denaturation determines the low temperature shift of the point for a sharp decrease of the Ca-ATPase activity and of the corresponding break for parameter 2A'zz as well as the dissociation point for the lipoprotein Ca-ATPase complex and the corresponding breaks on the Arrhenius plots for the solubilization parameter, alpha, and the order parameter of spin probes, S.
D000818:Animals; D001665:Binding Sites; D002118:Calcium / Q000378:metabolism*; D000252:Calcium-Transporting ATPases / Q000378:metabolism*; D004578:Electron Spin Resonance Spectroscopy; D007700:Kinetics; D008054:Lipid Peroxides / Q000378:metabolism*; D008074:Lipoproteins / Q000378:metabolism*; D009132:Muscles / Q000378:metabolism; D011817:Rabbits; D012519:Sarcoplasmic Reticulum / Q000378:metabolism*; D013816:Thermodynamics
D008054:Lipid Peroxides; D008074:Lipoproteins; D000252:Calcium-Transporting ATPases; D002118:Calcium
Modifikatsiia fermentnoĭ sistemy transporta Ca2+ v sarkoplazmaticheskom retikulume pri perekisnom okislenii lipidov. Izmenenie molekuliarnoĭ organizatsii lipoproteidnogo kompleksa Ca-ATPazy.