DNA-platinum interactions in vitro with trans- and cis-Pt(NH3)2Cl2. 
In the present study the nature and the hydrolysis of DNA-Pt complexes with the platinum compounds, [Pt(dien)Cl]Cl, trans- and cis-Pt(NH3)2Cl2, using potentiometric chloride determinations, have been investigated.  The trans-Pt(NH3)2Cl2 and the [Pt(dien)Cl]Cl react with the GC planes at the N7(G) sites, while the cis-Pt(NH3)2Cl2 compound reacts with the GC planes and forms a chelate by using the N7(G) and O6(G) sites.  The complex is a specific 1:1 Pt:DNA adduct.  The platinum atom in cis-Pt(NH3)2Cl2 liberates both chlorine atoms on chelation.  A mechanism for the in vivo antitumor activity of the cis-Pt(NH3)2Cl2 is proposed and the structure activity relationship is discussed.