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A glutathione S-transferase with activity towards cis-1,2- dichloroepoxyethane is involved in isoprene utilization by Rhodococcus sp. strain AD45

Author: Hylckama Vlieg, J.E.T. van · Kingma, J. · Wijngaard, A.J. van den · Janssen, D.B.
Type:article
Date:1998
Institution: Centraal Instituut voor Voedingsonderzoek TNO
Source:Applied and Environmental Microbiology, 8, 64, 2800-2805
Identifier: 234557
Keywords: Nutrition · 1,2 dichloroepoxyethane · Ethylene · Glutathione transferase · Industrial chemical · Isoprene · Unclassified drug · Biodegradation · Dechlorination · Detoxification · Enzyme activity · Enzyme isolation · Kinetics · Nonhuman · Biodegradation, Environmental · Butadienes · Epoxy Compounds · Glutathione Transferase · Hemiterpenes · Oxidation-Reduction · Pentanes · Rhodococcus · Negibacteria · Rhodococcus sp.

Abstract

Rhodococcus sp. strain AD45 was isolated from an enrichment culture on isoprene (2-methyl-1,3-butadiene). Isoprene-grown cells of strain AD45 oxidized isoprene to 3,4-epoxy-3-methyl-1-butene, cis-1,2-dichloroethene to cis-1,2-dichloroepoxyethane, and trans-1,2-dichloroethene to trans-1,2- dichloroepoxyethane. Isoprene-grown cells also degraded cis-1,2- dichloroepoxyethane and trans-1,2-dichloroepoxyethane. All organic chlorine was liberated as chloride during degradation of cis-1,2-dichloroepoxyethane, A glutathione (GSH)-dependent activity towards 3,4-epoxy-3-methyl-1-butene, epoxypropane, cis-1,2-dichloroepoxyethane, and trans-1,2-dichloroepoxyethane was detected in cell extracts of cultures grown on isoprene and 3,4-epoxy-3- methyl-1-butene. The epoxide-degrading activity of strain AD45 was irreversibly lost upon incubation of cells with 1,2-epoxyhexane. A conjugate of GSH and 1,2-epoxyhexane was detected in cell extracts of cells exposed to 1,2-epoxyhexane, indicating that GSH is the physiological cofactor of the epoxide-transforming activity. The results indicate that a GSH S-transferase is involved in the metabolism of isoprene and that the enzyme can detoxify reactive epoxides produced by monooxygenation of chlorinated ethenes.