Identification of Sudan III-(deoxy)-guanosine adducts formed in situ in a reaction with no catalyst

Abstract

Incubation of guanosine and Sudan III induces the formation of a stable adduct, which may be identified using a spectrophotometric technique and mass spectroscopy. The high nucleophilicity of the C-8 position and its proximity to N-7 makes the site susceptible to a nucleophilic attack, which explains the S(N)2 reaction detected between guanosine and Sudan III dye. In addition, direct interaction of Sudan III with calf thymus DNA was monitored using a simple spectrophotometric technique. The results presented indicate that a simple modification of the chemical structure of Sudan I (monoazo dye) to Sudan III (diazo dye) markedly alters reactivity towards nitrogenous DNA bases.