The catechol and protocatechuate branches of the β-ketoadipate pathway and its regulation in P. stutzeri A1501. (A) Localization of the gene clusters involved in degradation of benzoate and 4-hydroxybenzoate on a linear map of the chromosome. (B) Predicted biochemical steps for the catechol and protocatechuate pathways in P. stutzeri A1501. The question mark indicates an unknown mechanism that may be involved in the regulation of cat genes. Inactivation of pcaD is shown by "× " and accumulations of the intermediates catechol and cis, cis-muconate in the supernatants of the pcaD mutant are shown by red vertical arrows. Genes whose expression is under catabolite repression control (Crc) are indicated by "⊥".