Dibenzo-p-dioxin and its chlorinated relatives are chemically stable and accumulate in milk and throughout the food chain, creating significant health concern. A chlorinated relative of Dibenzo-p-dioxin, 2,3,7,8-tetrachloro-dibenzo-p-dioxin, was involved in a 1976 explosion in Seveso, Italy, creating widespread major health problems. Dibenzo-p-dioxins are generated as by-products in the manufacturing of herbicides, insecticides, fungicides, paper pulp bleaching, and in incineration.
Sphingomonas sp. RW1 degrades dibenzo-p-dioxin through cleavage of the product of angular dioxygenation to catechol and 2-hydroxymuconate (Wittich et al., 1992). A similar pathway is known for diphenyl ether.
The following is a text-format dibenzo-p-dioxin pathway map. An organism which can initiate the pathway is 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 (6k) format.
Dibenzo-p-dioxin
Sphingomonas sp. RW1
|
|
|
| dioxin dioxygenase
|
|
v
2,2',3-Trihydroxydiphenyl-ether
(2,2',3-THD-ether)
|
|
| 2,2',3-trihydroxy-
| biphenyl dioxygenase
|
|
v
2-Hydroxy-6-oxo-6-(2-hydroxyphenoxy)-
hexa-2,4-dienoate
|
|
| 2-hydroxy-6-oxo-
| 6-(2-hydroxyphenoxy)-
| hexa-2,4-dienoate esterase
|
|
v
Catechol + 2-Hydroxymuconate
| |
| |
| |
| |
| |
| |
v v
to the Intermediary
Nitrobenzene Metabolism
Pathway (KEGG)
Page Author: Greg S. Bill
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