Characterization of dugong liver ferritin

Dugong liver contains very high levels of iron (up to 71 000 mu g g(-1) dry wt). Generally, iron is stored in the protein ferritin and the insoluble m aterial hemosiderin. Histological studies indicated dense deposit of iron i n the tissue, without evidence of the tissue damage normally associated wit h very high iron levels. The speciation studies on iron were carried out by Mossbauer spectroscopy. The size distribution and iron core crystallinity of the ferritin were also determined using a transmission electron microsco pe. Mossbauer spectra of purified ferritin at 78 K indicated the presence o f ferrihydrite (5Fe(2)O(3). 9H(2)O) rather than geothite-like (alpha-FeOOH) iron oxide. The Mossbauer spectra of a sample of dugong liver tissue indic ated the presence of a goethite-like iron phase related to that found in tr ansfused human thalassemic patients. The iron core study indicated that pur ified dugong ferritin had a limited crystallinity. The characteristics of p urified 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 a bility of the Liver tissue to withstand the high concentration of iron in t he tissue without apparently damaging the tissue deserves further study. (C ) 1999 Elsevier Science B.V. All rights reserved.