Ali Heydari - Department of Chemistry, University of Sistan&Baluchestan, Zahedan, Iran
Hassan Mansouri-Torshizi - Department of Chemistry, University of Sistan&Baluchestan, Zahedan, Iran

The development of new metal complexes which can selectivity interact with nucleic acid is of muchcurrent interest. Among the other transition metal complexes, palladium complexes with favorableanticancer activity are good models analogues for Pt(II) complexes.[1-3] Therefore a novel palladium (II)complex has been synthesized with Valine (Val) and acetyleaceton (acac) by reaction of Na2[PdCl4] andsodium salts of valine and acac. Thus a complex of the type [Pd(acac)(Val)] has been obtained. Thiswater-soluble and neutral complex was characterized by spectroscopic and non-spectroscopic methods.Cytotoxicity effect of the Pd(II) complex toward cancer cell line of K562 was measured using MTT assay.The interaction of this complex with calf thymus DNA (CT-DNA) were investigated under physiologicalcondition in Tris-HCl buffer using spectroscopic methods including UV-Vis absorption spectroscopy,ethidium bromide displacement and fluorescence titration spectra. The results obtained from theseanalyses indicated that this complex effectively interact with CT-DNA at low concentrations.Fluorescence titration revealed that binding constant (Kb), apparent biomolecular quenching constant (Kq)and number of binding sites (n) for CT-DNA. Also, thermodynamic parameters data suggested thathydrogen binding and Van der Waals force play a major role in the association of CT-DNA-Pd(II)complex. The complex exhibited groove binding mode with CT-DNA.

Palladium(II) complex; DNA binding; cytotoxicity; Valine