Transport of Fe2+ across lipid bilayers: possible role of free fatty acids.
Fatty acids can form lipid-soluble complexes with Fe2+. Incorporation of fatty acids into phosphatidylcholine/cholesterol liposomes renders them permeable to Fe2+. Of several fatty acids tested, the most effective Fe2+ carriers were linoleic and oleic acids followed, in decreasing order of efficacy, by linolenic, myristic, arachidonic and palmitic acids. The initial Fe2+ transport rate for oleic acid depends on free Fe2+ in the medium which in turn shows a strong pH dependence above pH 7.0. The overall pH dependence of Fe2+ transport for several fatty acids shows an optimum near 6.9. Fe2+ transport catalysed by oleic acid can be inhibited by high NaCl concentrations but not 1 mM Co2+. It is suggested that free fatty acids may act as mediators of Fe2+ transport across biological membranes, particularly isolated intestinal brush-border membrane.
D001205:Ascorbic Acid / Q000378:metabolism; D001692:Biological Transport / Q000187:drug effects; D003035:Cobalt / Q000494:pharmacology; D005230:Fatty Acids, Nonesterified / Q000502:physiology; D006863:Hydrogen-Ion Concentration; D007501:Iron / Q000378:metabolism*; D007700:Kinetics; D019787:Linoleic Acid; D008041:Linoleic Acids / Q000378:metabolism; D008051:Lipid Bilayers / Q000378:metabolism*; D008081:Liposomes / Q000378:metabolism*; D008563:Membrane Lipids / Q000502:physiology*; D019301:Oleic Acid; D009829:Oleic Acids / Q000378:metabolism; D012965:Sodium Chloride / Q000494:pharmacology
D005230:Fatty Acids, Nonesterified; D008041:Linoleic Acids; D008051:Lipid Bilayers; D008081:Liposomes; D008563:Membrane Lipids; D009829:Oleic Acids; D019301:Oleic Acid; D003035:Cobalt; D012965:Sodium Chloride; D019787:Linoleic Acid; D007501:Iron; D001205:Ascorbic Acid