Characterization of dugong liver ferritin Original Research Article

Dugong liver contains very high levels of iron (up to 71 000 μg g−1 dry wt). Generally, iron is stored in the protein ferritin and the insoluble material hemosiderin. Histological studies indicated dense deposit of iron in the tissue, without evidence of the tissue damage normally associated with very high iron levels. The speciation studies on iron were carried out by Mössbauer spectroscopy. The size distribution and iron core crystallinity of the ferritin were also determined using a transmission electron microscope. Mössbauer spectra of purified ferritin at 78 K indicated the presence of ferrihydrite (5Fe2O3·9H2O) rather than geothite-like (α-FeOOH) iron oxide. The Mössbauer spectra of a sample of dugong liver tissue indicated the presence of a goethite-like iron phase related to that found in transfused human thalassemic patients. The iron core study indicated that purified dugong ferritin had a limited crystallinity. The characteristics of purified dugong ferritin are similar to other mammalian ferritins, based on amino acids determination of the ferritin protein cage. The naturally high level of iron in its food is reflected in the high liver iron values. The ability of the liver tissue to withstand the high concentration of iron in the tissue without apparently damaging the tissue deserves further study.