Paraoxon deethylation in the metabolism of parathion

Induction of paraoxon dealkylation by hexachlorobenzene (HCB) and mirex

“…A CI3CCOOH scan of an incubate using [14C]paraoxon with microsomes from HCB-induced animals is presented in Figure 2. When the cofactors were omitted, only DEP and paraoxon were present, confirming that DEO production is dependent on mixed function oxidase activity, as reported by Appleton and Nakatsugawa (1972) significantly different (P < 0.05) from controls with DEO formation exhibiting the largest increase. Body weight gain was not significantly greater in the treated group.…”

“…Dealkylation of organophosphate insecticides is believed to occur via the microsomal mixed function oxidase system Bureau of Chemical Safety, Foods Directorate, Health Protection Branch, Ottawa, Ontario, Canada, KlA 0L2. and a cytoplasmic glutathione transferase (Appleton and Nakatsugawa, 1972). Ku and Dahm (1973) have reported that O-dealkylation is increased considerably after administration of phenobarbital and other inducers, while the glutathione-requiring system is unaffected.…”

Microsomal Oxidation and Insecticide Metabolism

“…While the studies of demethylation of the 2-methoxy group seems possible in view of the dual dealkylation with methoxychlor and ethoxychlor. Contrary to the earlier belief that the importance of dealkylation in organophosphate metabolism was limited to dimethyl esters, accumulating evidence indicates that the removal of alkyl groups is also a significant metabolic pathway for higher homologues (Appleton and Nakatsugawa, 1972). Microsomal oxidases seem to dealkylate a number of organophosphates, including certain dimethyl triesters (Fig.…”

Rapid method for estimating microsomal oxidase activity in the housefly with carbon-14-labeled parathion as substrate

“…Phenyl-14C-labeled paraoxon (22.5 mCi/mmol) was a gift from Dr. T. Nakatsugawa, State University of New York, Syracuse, N. Y. It was synthesized from [l-14C]-4-nitrophenol and purified by column chromatography (Appleton and Nakatsugawa, 1972). NADPH was purchased from Sigma Chemical Corp., St. Louis, Mo.…”