Iron does not bind to the Apo-B protein of low-density lipoprotein.
BACKGROUND
Epidemiological and experimental evidence suggests that (nontransferrin-bound) iron plays an important role in atherogenesis by catalysing peroxidation of low-density lipoprotein (LDL). However, the mechanism of the interaction of iron and LDL is unclear. Iron has to be in the closest vicinity of LDL in order to catalyse the formation of the short-lived hydroxyl. In this study we investigated whether iron can bind to LDL in order to facilitate LDL peroxidation.


METHODS
LDL and [(59)Fe]ferric citrate were incubated at 37 degrees C and pH 7.4 for 30 min. Unbound [(59)Fe]ferric citrate was separated from LDL using a Sephadex G25-M column. Activity of [59Fe]ferric citrate was measured in the collected fractions. A control experiment was performed using albumin instead of LDL.


CONCLUSIONS
No binding was observed between iron, as a low molecular weight Fe(III) complex, and LDL. As a control albumin was able to bind iron, it seems evident that interaction of iron with LDL will involve other iron complexes.
de Valk
B
B
Department of Internal Medicine and Eijkman-Winkler Institute for Microbiology, Infectious Diseases and Inflammation, University Medical Center Utrecht, PO Box 85500, 3508 GA Utrecht, The Netherlands.
Leus
F R
FR
Voorbij
H A M
HA
Marx
J J M
JJ
D001055:Apolipoproteins B / Q000378:metabolism*; D001161:Arteriosclerosis / Q000378:metabolism; D006801:Humans; D007501:Iron / Q000737:chemistry / Q000378:metabolism*; D007504:Iron Radioisotopes; D015227:Lipid Peroxidation / Q000502:physiology; D008077:Lipoproteins, LDL / Q000378:metabolism*; D008970:Molecular Weight
D001055:Apolipoproteins B; D007504:Iron Radioisotopes; D008077:Lipoproteins, LDL; D007501:Iron