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.
van Hylckama Vlieg
J E
JE
Department of Biochemistry, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, 9747 AG Groningen, The Netherlands.
Kingma
J
J
van den Wijngaard
A J
AJ
Janssen
D B
DB
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