THE CHEMILUMINESCENCE ASSAY OF LIPID-PEROXIDATION PRODUCTS IN HUMAN BLOOD-PLASMA LIPOPROTEINS

A chemiluminescence (CL) flash kinetics on the addition of Fe2+ ions into oxidized low density lipoprotein (LDL) suspension has been studied. LDL oxidation was carried out at 37 degrees C without and in the presence of 5 or 50 mu M of CU.(2+) It has been found that under certain experimental conditions (the addition of excess iron ions, more than 1 mM) the amplitude of CL flash depended almost linearly (1) on the concentration of oxidized LDL and (2) on the extent of LDL oxidation measured as diene conjugates (DC) and 2-thiobarbituric acid-reactive substance (TBARS) accumulation. The corresponding correlation coefficients were: for TBARS - 0.94 and for DC - 0.97, in the case of LDL autooxidation; 0.72 and 0.98, in the case of copper-induced LDL oxidation. A sensitivity of the CL method was shown to be significantly enhanced (by more than two orders) in the presence of CL sensitizer- 2,3,5,6-1H,4H-tetrahydro-9-(2'-benzoimidazolyl)-quinolizin-(9,9a,1-gh)coumarin.