In vitro metabolism of 1,2-dihaloethanes to ethylene

ORCiD

0000-0001-9010-5970

Document Type

Article

Publication Title

Drug Metabolism and Disposition

ISSN

0090-9556

Volume

7

Issue

4

First Page

199

Last Page

203

Publication Date

7-1-1979

Abstract

1,2-Dichloroethane (DCE), a solvent and byproduct of the manufacture of polymers, and 1,2-dibromoethane, a soil fumigant, are known to be metabolized by conjugation with glutathione (GSH) to yield mercapturic acid derivatives. An alternate route of metabolism of the GSH conjugate involves beta-elimination of halide ion to form an olefin. In the present study, ethylene production from DCE was measured by gas chromatography in rat tissues as an index of this latter route of metabolism. The rate of enzymic ethylene production was linear over a 1-hr incubation time and from 1 to 8 mg of protein per ml reaction volume. The temperature optimum for ethylene formation from DCE was 55 degrees C and no distinct pH optimum was observed. DCE metabolism was highly dependent on the presence of reduced GSH. Metabolic activity was limited to hepatic and renal cytosolic fractions. The reaction was inhibited only by p-chloromercuribenzoic acid and by diethyl maleate and methyl iodide, which are substrates for GSH S-transferases. (S-(-2-Chloroethyl)-DL-cysteine . HCl, an analog of the conjugate formed from DCE and GSH, was nonenzymically converted to ethylene.

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