Nuclear magnetic relaxation dispersion of ferritin and ferritin-like magnetic particle solutions: a pH-effect study.
The relaxation mechanism of water protons in the presence of ferritin is still being debated. In this work, the pH dependence of the relaxation induced by ferritin and Fercayl, a ferritin-like akaganeite particle, is studied through T1 and T2 nuclear magnetic relaxation dispersion (NMRD) profiles. To differing extents, the relaxation brought about by both systems is significantly affected by pH. A proton exchange time of 33 ns (at pH 6 and 37 degrees C) is deduced from the fittings of Fercayl T1 NMRD profiles. The linearity of the relationship between 1/T2 and the magnetic field B0 for ferritin and Fercayl solutions is not altered by changes in pH. The parameters of this linearity strongly depend on pH for the latter, while remaining unchanged for the former. These results are interpreted in terms of an exchange between protons belonging to hydroxyl groups at the surface of the particle and bulk water protons.
Gossuin
Y
Y
Department of Biological Physics, University of Mons-Hainaut, Mons, Belgium. yves.gossuin@umh.ac.be
Roch
A
A
Lo Bue
F
F
Muller
R N
RN
Gillis
P
P
D000818:Animals; D001052:Apoferritins / Q000378:metabolism; D005290:Ferric Compounds / Q000378:metabolism*; D005293:Ferritins / Q000378:metabolism*; D006736:Horses; D006863:Hydrogen-Ion Concentration; D007089:Image Enhancement; D009682:Magnetic Resonance Spectroscopy; D014018:Tissue Distribution
D005290:Ferric Compounds; C000499:ferric oxide; C092844:ferric oxyhydroxide; D005293:Ferritins; D001052:Apoferritins