Competitive binding of the anticancer drug titanocene dichloride to N,N-ethylenebis(o-hydroxyphenylglycine) and adenosine triphosphate: a model for Ti-IV uptake and release by transferrin

H-1 and P-31 NMR studies show that in aqueous solution the anticancer agent titanocene dichloride (Cp2TiCl2) binds selectively to N,N'-ethylenebis(o-hydroxyphenylglycine) (H(4)ehpg) at neutral pH, but preferentially to adenosine triphosphate (ATP) at pH* values below 5.1; intermolecular Ti-IV transfer from [Ti-IV(ehpg)(H2O)] to ATP occurs at acidic pH values.