Abstract: Nitrosulfophenol Sis advocated as the chemical model in the investigation of carcinogenic non-aminoazo dyes. Oxidative cleavage reaction of Nitrosulfophenol Sis carried out in the enzymic biotransform model-HRP/ H₂O₂ system, and the product, ultimate carcinogens aromicdiazonium ions, which bind to DNAis identified by visible spectra, capillary zone electrophoresis, electroanalytical chemical and other methods. The rate of oxidative cleavage depends on pH, temperature, and the concentrations of HRPand H₂O₂, then their optional oxidative conditions are discussed in detail. The inhibition and activation of various biological substances to the reaction is also investigated.

Key words: Carcinogen, Nitrosulfophenol S, Aromicdiazonium ions, Peroxidase.