Peroxidase-activated carcinogenic azo dye Sudan I (Solvent Yellow 14) binds to guanosine in transfer ribonucleic acid.

Peroxidase in the presence of hydrogen peroxide catalyzes in vitro the activation of the carcinogenic azo dye Sudan I (1-phenylazo-2-hydroxynaphthalen) to tRNA-, homopolyribonucleotide- and 5'-monophosphate nucleoside-bound products. tRNA, poly G and guanosine 5'-monophosphate modified by activated Sudan I become colored and have an absorption maximum of approx. 480 nm. Cochromatographic analysis of adducts obtained by a reaction with tRNA and guanosine 5'-monophosphate on a thin layer of cellulose showed that the major Sudan I-tRNA adduct was formed by a reaction of activated Sudan I with guanosine in tRNA. The radical mechanism of the binding of the Sudan I molecule, containing the whole azo aromatic system, to nucleic acids is discussed.