MISHANDLING OF COPPER BY ALBUMIN: ROLE IN REDOX-CYCLING AND OXIDATIVE STRESS IN PREECLAMPSIA PLASMA

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Abstract
Objective. To test the hypothesis that enhanced oxidative stress during pregnancies complicated by preeclampsia is associated with improper copper (Cu) binding by plasma albumin, resulting in enhanced Cu redox-cycling activity and that altered Cu binding, in turn, is caused by interactions of excessive amounts of free fatty acids with albumin.Study Design. We studied binding and redox-cycling activity of Cu in 17 normal pregnancy and 17 preeclampsia plasma samples. Binding of exogenous Cu in plasma samples was quantified indirectly using spectrophotometric measurements of its complex with a specific chelator of Cu(I), bathocuproine disulfonate. Redox-cycling activity of Cu in plasma samples was estimated by electron paramagnetic resonance (EPR) spectroscopy of ascorbate radicals formed during one-electron oxidation of ascorbate by redox-active catalytic Cu. Formation of Cu/albumin complexes in model systems in the presence and absence of fatty acids was studied using EPR spectroscopy of Cu(II)/albumin.Res...