CORE-LEVEL PHOTOELECTRON-SPECTROSCOPY ON THE LANTHANIDE-INDUCED HYDROLYSIS OF DNA

The electronic structures of the complexes of diphenyl phosphate (DPP) , a model compound of DNA, with lanthanide ions have been investigated to shed light on the mechanism of the cerium (IV)-induced nonenzymati c hydrolysis of DNA. Binding energies of the P 2p core level of DPP we re 134.2 eV for the complexes with La(III), Eu(III), and Lu(III), and was 134.4 eV for the Ce(IV) complex, when the metal/DPP molar ratio wa s 1:1. When the molar ratio was increased, only Ce(IV), the most activ e metal ion for DNA hydrolysis, showed a chemical shift of similar to 0.5 eV toward the higher binding energy region. The chemical shift of similar to 0.5 eV toward the higher binding energy region. The chemica l shift was due to the systematic increase in the intensity of the hig her binding energy component. The observed change in the electronic st ructure of the DPP-Ce(IV) complex may be related to the superb ability of Ce(IV) for the hydrolysis of DNA. (C) 1996 American Institute of P hysics.