In vitro lipid oxidation modifies proteins and functional properties of sarcoplasmic reticulum.
Changes in protein and fatty acid compositions of flounder sarcoplasmic reticulum during NADH plus ascorbate-dependent lipid peroxidation in vitro were related to the ability of the sarcoplasmic reticulum to sequester Ca+2. Progressive accumulation of high-molecular-weight protein components occurred concomitantly with loss of Ca+2-sequestering activity. Part of this polymerized protein may be the dimer or trimer of Ca+2, Mg+2-ATPase. Loss in Ca+2, Mg+2-ATPase protein could account for over 60% of the polymerized protein. Rate of loss of polyunsaturated fatty acids was C22:6 greater than C20:4 greater than C20:5 greater than C22:5. Loss of polyunsaturated fatty acids and accumulation of thiobarbituric acid-reactive substances occurred concomitantly with protein polymerization.
D000818:Animals; D017301:Ca(2+) Mg(2+)-ATPase / Q000378:metabolism; D002118:Calcium / Q000378:metabolism; D000252:Calcium-Transporting ATPases / Q000378:metabolism; D005231:Fatty Acids, Unsaturated / Q000378:metabolism; D005399:Fishes / Q000378:metabolism; D066298:In Vitro Techniques; D008054:Lipid Peroxides / Q000378:metabolism*; D011108:Polymers / Q000378:metabolism; D011506:Proteins / Q000378:metabolism*; D012519:Sarcoplasmic Reticulum / Q000378:metabolism*
D005231:Fatty Acids, Unsaturated; D008054:Lipid Peroxides; D011108:Polymers; D011506:Proteins; D017301:Ca(2+) Mg(2+)-ATPase; D000252:Calcium-Transporting ATPases; D002118:Calcium