Fig. 3

Lateral and angular dioxygenation pathway for metabolism of dibenzofuran and dibenzo-p-dioxin, respectively, from the proposed scheme of Becher et al. (2000) and Field and Sierra-Alvarez (2008). Product in parenthesis undergoes spontaneous transformation due to its instability. Dibenzofuran-1,2-dioxygenase (1), 1,2-dihydroxybenzofuran dioxygenase (2), 2-hydroxy-4-(3′-oxo-3′H-benzofuran-2′yliden(but-2-enoic acid hydrolase (3), dibenzo-p-dioxin-1,10a-dioxygenase (4), 1,10a-dihydroxy-1-hydrodibenzo-p-dioxin dehydrogenase (5), 2,2′,3-trihydroxydiphenyl ether dioxygenase (6), and 2-hydroxy-6-oxo-6-(2-hydroxyphenoxy)-hexa-2,4-dienoic acid hydrolase (7)