CHEMICAL-STRUCTURE AND GENOTOXICITY - STUDIES OF THE SOS CHROMOTEST

Analyses of a data base consisting of 461 chemicals tested in the SOS chromotest with MULTICASE resulted in the development of an SAR model that displayed a highly significant concordance (87.3%) between experi mental and predicted results of chemicals not included in the model. A n analysis of the nature of the biophores and their modulators reveale d that electrophilicity and structural features affecting: (a) accessi bility of the electrophile to the nucleophilic site on the DNA; and (b ) the bulkiness of the DNA adduct were factors determining the probabi lity that a chemical would induce DNA error prone repair and if so the extent of this activity. Additional analyses indicated that there wer e significant mechanistic similarities between the SOS chromotest and mutations in Salmonella as determined in the standard ('Ames') assay.