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R. Racine, Philippe Moisy, F. Paquet, H. Métivier, Charles Madic

In vitro study of the interaction between neptunium ions and aposerumtransferrin by absorption spectrophotometry and ultrafiltration: the case of Np(V)

The interaction between Np(V) and human aposerumtransferrin (apoTf) was studied in vitro under physiological conditions (37°C, pH 7.4, [NaCl]=0.15M, [HEPES]=5×10^-2M) by UV-visible and near-IR absorption spectrophotometry and by ultrafiltration. It was found that Np(V) was bound in small fraction (<12) to apoTf, and that the role of carbonate and citrate anions in binding is more competitive than synergistic. The complexes NpO₂CO₃^- and NpO₂Cit^2- tend to form rather than the Np(V)-apoTf complex. Np(V) binding on apoTf appears to be pH-dependent and reversible. Displacement experiments with Fe^IIINTA showed non-specific binding, suggesting a weak interaction between Np(V) and apoTf different from the reactions involving transferrin-specific sites with other metallic ions, such as Fe(III). The low overall charge, the size and the geometry of the linear di-oxocation NpO₂⁺ could account for the weak interaction between Np(V) and human transferrin.

Radiochimica Acta, Oldenbourg Wissenschaftsverlag

Print ISSN: 0033-8230
Volume: 91, 02/2003
Pages: 115

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