DDT dehydrochlorinase. I. Isolation, chemical properties, and spectrophotometric assay.

The dehydrochlorination of 1 , 1 , I-trichloro-2,2-bis(p-chlorophenyl)ethane to its nontoxic, ethylenic analogue, DDE,* by extracts of DDT-resistant houseflies (1Musca domestica) was first demonstrated by Sternburg et al. (I). It was shown that this system was GSH-dependent and that no DDT dehydrochlorinase could be detected in DDT-susceptible flies by the means then available. The titer of DDT dehydrochlorinase in various strains of flies was directly proportional to the degree of resistance to DDT (2), and it was concluded that the presence of this detoxicating system was a factor of major importance in the survival of populations of houseflies exposed to DDT. The reaction is as follows: