Intradiol dioxygenases reaction mechanisms

Figure 18-22 Some possible intermediates in the action of extradiol (left) and intradiol (right) aromatic dioxygenases. Although the steps depict the flow of pairs of electrons during the formation and reaction of peroxide intermediates, the mechanisms probably involve free radicals whose formation is initiated by 02. The asterisks show how two atoms of labeled oxygen can be incorporated into final products.

The intradiol cleaving catechol dioxygenases are bacterial iron-containing enzymes that serve as a component of nature s mechanism for degrading aromatic compounds in the environment. These enzymes, represented by catechol 1,2-dioxygenase (CTD) and protocatechuate(3,4-dihydroxybenzoate) 3,4-dioxygenase (PCD), catalyze the reaction... 

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