The effect of EDTA-Fe(III) complexes with different chemical structure on the lipid peroxidation in brain microsomes.

Unlike EDTA-Fe(III) (1:1), the oxidized form of EDTA-Fe(II) complex enhanced lipid peroxidation in brain microsomes. Mossbauer spectroscopy and electron paramagnetic resonance analysis of oxidized EDTA-Fe(II), capable of inducing lipid peroxidation, showed the presence of EDTA-Fe(III) complex, which was different from the separately prepared (not oxidized) EDTA-Fe(III). Lipid peroxidation initiated by the oxidized EDTA-Fe(II) complex was dependent on the presence of NAD(P)H and functionally intact microsomes. No inhibitory effect was found by generally used free radical scavengers and catalase. Our results clearly indicate that the chemically different EDTA-Fe(III) complexes differ in their capability of initiating the NAD(P)H-dependent lipid peroxidation in brain microsomes.