FIG. 1.
Degradation of toluene and related hydrocarbons as specified by the TOL pWW0 plasmid and schematic gene organization. Toluene or xylenes are oxidized to benzoate or toluates through the upper pathway. The latter compounds are subsequently oxidized and decarboxylated to yield catechols, which upon ring cleavage are channeled to Krebs cycle intermediates by the enzymes encoded in the meta pathway. R1 = R2 = H; R1 = CH3, R2 = H; R1 = H, R2 = CH3; R1 = CH2-CH3, R2 = H. The inverted triangle indicates the inactivated step in pWW0:xylE::Km, which allows the transformation of m-xylene into 3-methylcatechol.