The formation of reactive metabolites through biotransformation is the suspected 
cause of many adverse drug reactions. Testing for the propensity of a drug to 
form reactive metabolites has increasingly become an integral part of 
lead-optimization strategy in drug discovery. DNA reactivity is one undesirable 
facet of a drug or its metabolites and can lead to increased risk of cancer and 
reproductive toxicity. Many drugs are metabolized by cytochromes P450 in the 
liver and other tissues, and these reactions can generate hard electrophiles. 
These hard electrophilic reactive metabolites may react with DNA and may be 
detected in standard in vitro genotoxicity assays; however, the majority of 
these assays fall short due to the use of animal-derived organ extracts that 
inadequately represent human metabolism. The current study describes the 
development of bacterial systems that efficiently detect DNA-damaging 
electrophilic reactive metabolites generated by human P450 biotransformation. 
These assays use a GFP reporter system that detects DNA damage through induction 
of the SOS response and a GFP reporter to control for cytotoxicity. Two human 
CYP1A2-competent prototypes presented here have appropriate characteristics for 
the detection of DNA-damaging reactive metabolites in a high-throughput manner. 
The advantages of this approach include a short assay time (120-180 min) with 
real-time measurement, sensitivity to small amounts of compound, and 
adaptability to a microplate format. These systems are suitable for 
high-throughput assays and can serve as prototypes for the development of future 
enhanced versions.