Synthesis and analysis of DNA chromium complexes

<p>Studies have shown that the key step, in the carcinogenicity and toxicity of Cr(VI) compounds is its intracellular reduction to Cr(III). The Cr(III) so produced causes the formation of DNA-Cr-Protein (DCP) crosslinks, which have been implicated in the initiation of carcinogenesis due to their persistence. The purpose of this project was to develop methods for the synthesis of Cr(III)-DNA complexes and their analysis. The complexes that were prepared were, DNA-Cr(III) by the method of reduction, and DNA-Cr(III), DNA-Cr(III) bipyridyl, and DNA-Cr(III) o-phenanthroline, prepared by direct substitution. The effects of concentration, temperature, dropping rate of the reductant, time, and ionic strength on the reaction, were also studied. The DNA-Cr(III) complexes that were formed were oxidized and the metal concentration was determined using a spectrophotometric method. The reduction method gives a chromium to base ratio of 1.90 and the substitution method gives a ratio of 0.61. The complexes are digested enzymatically and separated using HPLC.</p>