Metabolism of Benzene Hexachloride Isomers and Related Compounds In Vitro. II. Purification and Stereospecificity of House Fly Enzymes1

Abstract

Attempts were made to purify the house fly, Musca domestica L., enzymes that metabolize the α- and γ-isomers of 1,2,3,4,5,6-hexachlorocyclohexane (BHC) and the γ- and δ-isomers of 1,3,4,5,6- pentachlorocyclohex -1 - ene (PCCH) to unknown water-soluble substances in the presence of glutathione. Quantitative analyses of effluents from ion exchange columns indicated at least 3 enzyme systems that metabolize both α-BHC and γ-PCCH, with different ratios of metabolizing activity for the 2 substrates. The activity of enzymes from various ages of adult house flies demonstrated enzyme stereospecificity in the metabolism of α- and γ-BHC. The development of enzyme activity with the age of adult flies had no correlation with the lethal dosage of γ-BHC to flies of the same age. No large changes of enzyme activity for metabolism 7-PCCH were found through all stages of metamorphosis, α- and γ-BHC metabolizing enzymes were predominant in the adult stage only. DDT was dehydrochlorinated to DDE (2,2-bis-(pchlorophenyl) -1,1-dichloroethylene) with the enzymatic reaction system used for BHC. Several inhibition studies did not differentiate enzymes causing dehydrochlorination of DDT from those metabolizing BHC.