Differentiation between chelated and non-chelated DNA-Pt complexes by atomic absorption spectrophotometry.

As a continuation of our study of the properties of the cis-trans platinum series we have investigated the DNA-Pt complexes of [Pt(dien)Cl]Cl, cis-Pt (en)Cl2, cis-Pt (NH3)2Cl2 and K2[PtCl4] by atomic absorption spectrophotometry. The DNA-Pt complexes correspond to the saturation of the N7-(Guanine) sites. It has been found that the chelate complexes obtained with cis-Pt(en)Cl2, cis-Pt(NH3)2Cl1 and K2[PtCl4] show the same absorbance. The [Pt(dien)Cl]Cl and trans-Pt (NH3)2Cl2 which are bound to the N7 (tuanine) site only, show an absorbance greater than the chelate complexes by a factor of two. In addition, it has been possible in the case of the trans-Pt (NH3)CCl1 complex to follow the fixation of platinum to DNA by atomic absorption spectrophotometry. The result is similar to the ionic chlorine liberation procedure reported previously.