查看文章

The interaction of V^IVO-salts as well as of a few V^IVO(carrier)_n complexes with human serum transferrin (hTF) is studied focusing on the determination of the nature and stoichiometry of the binding of V^IVO²⁺ to hTF, as well as whether the conformation of hTF upon binding to V^IVO²⁺ or to its complexes is changed. Circular dichroism (CD) spectra measured for solutions containing V^IVO²⁺ and apo-hTF, and V^IVO–maltol and apo-hTF, clearly indicate that hTF–V^IVO–maltol ternary species form with a V^IVO:maltol stoichiometry of 1:1. For V^IVO salts and several V^IVO(carrier)_n complexes (carrier ligand=maltolato, dhp, picolinato and dipicolinato) (Hdhp=1,2-dimethyl-3-hydroxy-4-pyridinone) the maximum number of V^IVO²⁺ bound per mole of hTF is determined to be ~2 or lower in all cases. The binding of V^IVO to apo-hTF most certainly involves several amino acid residues of the Fe-binding site, and as concluded by …