Lysosomal and cytosolic ferritins. A biochemical and electron-spectroscopic study.
Cytosolic and lysosomal ferritin and haemosiderin were isolated from rat livers which had been iron-loaded by four intraperitoneal injections of iron-dextran. The cytosolic and lysosomal ferritins, prepared in a phosphate-free medium, were subjected to gel-filtration chromatography on Sepharose 6B, yielding four fractions: a cytosolic monomeric (CMF) and void-volume ferritin fraction (CVVF), and a lysosomal monomeric (LMF) and void-volume ferritin fraction (LVVF). Of each fraction the following aspects were examined: (a) immunoreactivity against specific antiserum; (b) the Fe/P mass ratio and the effect of dialysis on this ratio using electron probe micro-analysis (EPMA); (c) morphology and Fe-specific imaging using electron spectroscopic imaging (ESI) and electron energy loss spectroscopy (EELS). For haemosiderin one aspect, the Fe/P ratio, was determined before and after extensive purification. The following results were obtained (a) All ferritin fractions reacted with anti- (rat liver ferritin). (b) The Fe/P ratios as determined in CMF in an haemosiderin were not affected by dialysis or extensive purification, respectively. The Fe/P ratio in CVVF was affected by dialysis. In the lysosomal fractions, only a trace of phosphorus (LVVF) or no phosphorus (LMF) was detected. (c) Morphologically, CMF and CVVF were found to be rather homogeneous; the iron core diameters of both fractions were in the known size range.(ABSTRACT TRUNCATED AT 250 WORDS)
Ringeling
P L
PL
Department of Chemical Pathology, Erasmus University Rotterdam, The Netherlands.
Cleton
M I
MI
Kroos
M J
MJ
Sorber
L W
LW
de Bruyn
W C
WC
Harrison
P M
PM
van Eijk
H G
HG
D000818:Animals; D002850:Chromatography, Gel; D003600:Cytosol / Q000032:analysis*; D004577:Electron Probe Microanalysis; D005293:Ferritins / Q000302:isolation & purification; D006485:Hemosiderin / Q000302:isolation & purification; D007501:Iron / Q000032:analysis; D008099:Liver / Q000032:analysis; D008247:Lysosomes / Q000032:analysis*; D008297:Male; D008854:Microscopy, Electron; D010758:Phosphorus / Q000032:analysis; D051381:Rats; D011919:Rats, Inbred Strains
D010758:Phosphorus; D005293:Ferritins; D006485:Hemosiderin; D007501:Iron