Interaction of Insulin-Enhancing Vanadium Compounds with Human Serum holo-Transferrin

Citations Over TimeTop 10% of 2013 papers

Abstract

The interaction of VO(2+) ion and four insulin-enhancing compounds, [VO(ma)2], [VO(dhp)2], [VO(acac)2], and cis-[VO(pic)2(H2O)], where Hma, Hdhp, Hacac, and Hpic are maltol, 1,2-dimethyl-3-hydroxy-4(1H)-pyridinone, acetylacetone, and picolinic acid, with holo-transferrin (holo-hTf) was studied through the combined application of electron paramagnetic resonance (EPR) and density functional theory (DFT) methods. Since in holo-hTf all of the specific binding sites of transferrin are saturated by Fe(3+) ions, VO(2+) can interact with surface sites (here named sites C), probably via the coordination of His-N, Asp-COO(-), and Glu-COO(-) donors. In the ternary systems with the insulin-enhancing compounds, mixed species are observed with Hma, Hdhp, and Hpic with the formation of VOL2(holo-hTf), explained through the interaction of cis-[VOL2(H2O)] (L = ma, dhp) or cis-[VOL2(OH)](-) (L = pic) with an accessible His residue that replaces the monodentate H2O or OH(-) ligand. The residues of His-289, His-349, His-473, and His-606 seem the most probable candidates for the complexation of the cis-VOL2 moiety. The lack of a ternary complex with Hacac was attributed to the square-pyramidal structure of [VO(acac)2], which does not possess equatorial sites that can be replaced by the surface His-N. Since holo-transferrin is recognized by the transferrin receptor, the formation of ternary complexes between VO(2+) ion, a ligand L(-), and holo-hTf may be a way to transport vanadium compounds inside the cells.

Related Papers

• → Seasonal variation of the concentrations of maltol and maltol glucoside in leaves of Cercidiphyllum japonicum(1993)16 cited
• → The preparation and characterization of some imido- and diazenido-rhenium complexes of maltol. The X-ray crystal structure of [Re(maltol)2(NPh)(PPh3)][BPh4](1991)24 cited
• → Arene ruthenium complexes with picolinic acid, 1-aminoethylphosphonous acid and α-hydroxyketones. X-ray structure of [(η-1,3,5-C6Me3H3)RuCl(NC5H4CO2)](1993)23 cited
• → Determination of Maltol and Ethyl Maltol in Apple Juice by Gas-Liquid Chromatography(1968)2 cited
• → Ligand controlled synthesis of mixed-ligand oxovanadium(V) and oxovanadium(IV) complexes(2004)1 cited