Binding of iron to human red blood cell membranes.
The binding of Fe3+ to red cell membranes was studied in a system in which lipid peroxidation was proportional to Fe3+ concentration. Binding of Fe3+ was evaluated by labeling with 59FeCl3 and measurement of NMR water-proton relaxation times. Labeling with 59Fe showed that 95% of the Fe3+ was membrane bound at 100 microM FeCl3 in a 1.5 mg protein/ml membrane suspension. Both spin-lattice (T1) and spin-spin (T2) relaxation times decreased with increasing Fe3+ concentration. Addition of red cell membrane suspensions largely prevents the Fe3+ effect on relaxation times. Charge transfer to Fe3+ may occur at the membrane binding site with resultant decrease in the Fe3+ effect on water-proton relaxation times. These studies support the hypothesis that Fe3+ binds to the membrane and generates free radicals at the binding site.
Baysal
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E
Department of Pharmacology, New York University School of Medicine, NY 10016.
Sullivan
S G
SG
Stern
A
A
D000328:Adult; D004910:Erythrocyte Membrane / Q000378:metabolism*; D006801:Humans; D066298:In Vitro Techniques; D007501:Iron / Q000097:blood*; D015227:Lipid Peroxidation / Q000502:physiology; D009682:Magnetic Resonance Spectroscopy
D007501:Iron