Oxidation of low-density lipoprotein by Cu2+ and lipoxygenase: an electron spin resonance study |
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Authors: | B Kalyanaraman W E Antholine S Parthasarathy |
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Affiliation: | Department of Radiology, Medical College of Wisconsin, Milwaukee 53226. |
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Abstract: | The aim of this work was to obtain spectroscopic evidence for free radicals formed during copper ion- and lipoxygenase-catalyzed oxidation of the low-density lipoprotein. During the initial oxidation phase, a free-radical metabolite derived from the endogenous alpha-tocopherol present in the low-density lipoprotein was detected by the electron spin resonance technique. The divalent copper ions were bound to the residual EDTA present in the low-density lipoprotein and to the protein. Production of the alpha-tocopherol radical was suppressed in the presence of spin traps. Evidence for the low-density lipoprotein-lipid derived radicals was obtained by ESR-spin trapping methods. Implications of these findings in the oxidative modification of the low-density lipoprotein are discussed. |
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