title: Pathways for the degradation of m-cresol and p-cresol by Pseudomonas putida.
abstract: A comparison of the oxidation rates of various compounds by whole cells of Pseudomonas putida 3, 5 indicated that m-cresol is metabolized by oxidation to 3-hydroxybenzoate followed by hydroxylation to gentisate, the ring-fission substrate, when grown with 3, 5-xylenol. However, when m-cresol was the growth substrate, similar experiments suggested a different pathway involving a methyl-substituted catechol, and ring-fission by meta cleavage. Assays of ring-fission enzymes in cell-free extracts confirmed that different pathways are induced by the two growth substrates. 3, 5-Xylenol-grown cells contained high levels of gentisate oxygenase and only very small amounts of catechol oxygenase, whereas gentisate ocygenase could not be detected in m-cresol-grown cells, but levels of catechol oxygenase were greatly increased. Extracts of m-cresol-grown cells also contained 2-hydroxymuconic semialdehyde dehydrogenase and hydrolase, whose specificities enable them to metabolize the ring-fission products from catechol, 3-methylcatechol, and 4-methylcatechol. This catechol pathway is also used by m-cresol-grown cells for p-cresol metabolism. In contrast, the results for cells grown with p-cresol point to an alternative pathway involving oxidation to 4-hydroxybenzoate and hydrosylation to protocatechuate as ring-fission substrate. Extracts of these cells contained high levels of protocatechuate oxygenase and only small amounts of catechol oxygenase.
mesh_terms: D000272:Adipates / Q000031:analogs & derivatives; D001565:Benzoates / Q000378:metabolism; D002396:Catechols / Q000378:metabolism; D002474:Cell-Free System; D003408:Cresols / Q000378:metabolism*; D005841:Gentisates / Q000378:metabolism; D006867:Hydrolases / Q000378:metabolism; D006900:Hydroxylation; D010084:Oxidation-Reduction; D010088:Oxidoreductases / Q000378:metabolism; D010101:Oxygen Consumption; D010105:Oxygenases / Q000378:metabolism; D010636:Phenols / Q000378:metabolism; D011549:Pseudomonas / Q000201:enzymology / Q000378:metabolism*; D012988:Soil Microbiology; D013053:Spectrophotometry; D013237:Stereoisomerism; D013386:Succinates / Q000378:metabolism; D014871:Water Microbiology; D014992:Xylenes
chemical_list: D000272:Adipates; D001565:Benzoates; D002396:Catechols; D003408:Cresols; D005841:Gentisates; D010636:Phenols; D013386:Succinates; D014992:Xylenes; D010088:Oxidoreductases; D010105:Oxygenases; D006867:Hydrolases