Alkaline ability of guanosine and aome of its derivatives modified by the carcinogen N-acetoxyacetylaminofluorene

Abstract

The alkaline treatment of Guo, dGuo, dGMP and denatured DNA modified by N-acetoxyacetylaminofluorene (N-AcO-AAF) was performed in 0.1 M NaOH at 40°C. The kinetics of the reaction were followed by ultraviolet absorption and by chromatographic methods and were found different for the four products under study. Circular dichroimi spectra show differencee in the environment of acetylaminofluorene residue in these products. The alkaline treatment of Guo-AAF (end dGuo-AAF) leads to the formation of three products. These products were separated by thin layer chromatography and by HPLC and were characterized by spectroscopic methods. One is the already known unstable Guo-AF (and respectively dGuo-AF)(1). The other two products are relatively stable products of the transformation of Guo-AF (or dGuo-AF). These last ones present almost identical ultraviolet absorption spectra, but very different circular dichroism spectra.