Pentachlorophenol Family Degradation Pathway

Pentachlorophenol Family Pathway Map

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This pathway was contributed by Dr. Larry Wackett, University of Minnesota.

Pentachlorophenol (PCP) is a chlorinated insecticide and fungicide. It is used primarily to protect timber from fungal rot and wood boring insects. PCP is significantly toxic to mammals, plants, and many microorganisms. Despite this, bacteria have been identified that are resistant to relatively high PCP concentrations and can metabolize it to carbon dioxide and chloride. Bacteria have been used successfully in PCP bioremediation.

The Japanese Database for Environmental Fate of Chemicals has information on the rates and pathways of Biodegradation of Chlorophenols and Chlorobenzenes in Sediments. For a comprehensive treatment of microbial PCP metabolism, see K.A. McAllister, H. Lee & J.T. Trevors (1996) Biodegradation 7:1-40.

2,6-Dichlorohydroquinone 1,2-dioxygenase is an enzyme that catalyzes the oxidative cleavage of 2,6-dichlorohydroquinone. The site of cleavage was shown to occur between the 1 and 2 positions by Xun et al. (1999).

This is a text-format pentachlorophenol degradation pathway. Organisms which can initiate the pathway are given, but other organisms may also carry out later steps. Follow the links for more information on compounds or reactions. This map is also available in graphic (25k) format.

                                Pentachlorophenol
                                      (PCP)
                          Burkholderia cepacia AC1100
                         Flavobacterium sp. ATCC 39723
                                        |
                                        | pentachlorophenol
                                        | 4-monooxygenase
                                        |
                                        v
                         2,3,5,6-Tetrachlorohydroquinone
                                     (TeCH)
                                        |
                                        | tetrachloro-p-hydroquinone
                                        | reductive dehalogenase
                                        |
                                        v
                           2,3,6-Trichlorohydroquinone
                                     (TrCH)
                                        |
                                        | tetrachloro-p-hydroquinone
                                        | reductive dehalogenase
                                        |
           2,6-Dichlorophenol           |           2,4,6-Trichlorophenol
               (2,6-DCP)      \         |         /      (2,4,6-TCP)
                               \        |        /
                                \       |       /
    chlorophenol 4-monooxygenase \      |      / chlorophenol 4-monooxygenase
                                  \     |     /
                                   \    |    /
                                    \   |   /
                                     \  |  /
                                      \ | /
                                        v
                             2,6-Dichlorohydroquinone
                                     (DiCH)
                                        |
                                        |
                                        | 2,6-DiCH dioxygenase
                                        |
                                        |
                                        v
                             [(2E,4E)-1,5-Dichloro-3-
                           hydroxymuconic semialdehyde]
                                        |
                                        |
                                        | spontaneous hydrolysis
                                        |
                                        |
                                        v
                              2-Chloromaleylacetate
                                        |
                                        |
                                        | maleylacetate
                                        | reductase
                                        |
       From the                         v
       Bromoxynil Pathway  -----> Maleylacetate
                                        |
                                        |
                                        | maleylacetate
                                        | reductase
                                        |
                                        v
                                  3-Oxoadipate
                                        |
                                        |
                                        |
                                        |
                                        v
                                   Intermediary
                                    Metabolism
                                      (KEGG)

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Page Author(s): Yuemo Zeng

April 17, 2013 Contact Us

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