A glutathione S-transferase with activity towards cis-1, 2-dichloroepoxyethane is involved in isoprene utilization by Rhodococcus sp. strain AD45.
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.
Department of Biochemistry, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, 9747 AG Groningen, The Netherlands.
J E
JE
van Hylckama Vlieg
J
J
Kingma
A J
AJ
van den Wijngaard
D B
DB
Janssen
D001673:Biodegradation, Environmental; D002070:Butadienes / Q000378:metabolism*; D004852:Epoxy Compounds / Q000378:metabolism*; D005982:Glutathione Transferase / Q000378:metabolism*; D045782:Hemiterpenes; D010084:Oxidation-Reduction; D010420:Pentanes; D012240:Rhodococcus / Q000201:enzymology* / Q000254:growth & development / Q000302:isolation & purification
D002070:Butadienes; D004852:Epoxy Compounds; D045782:Hemiterpenes; D010420:Pentanes; C005059:isoprene; D005982:Glutathione Transferase