title: Variability in the enzyme properties of Pseudomonas aeruginosa strain 2x oxidizing p-xylene.
abstract: A culture of Pseudomonas aeruginosa 2x was observed for its spontaneous variability for growth on p-xylene and the intermediate products of its metabolism. The highest variability was found for ability to grow on p-xylene and pyrocatechol, and a variability an order of magnitude lower was found for ability to grow on protocatechuate and p-toluate. No variability was found for the character "ability to grow on p-hydroxybenzoate." The activity of the key enzymes for the oxidation of p-xylene was studied in p-xylene-negative strains. The difference between the p-xylene-positive wild type strain and the spontaneous p-xylene-negative strains was found to be linked to changes in the regulatory mechanisms for several enzymes: p-xylene methylhydroxylase and the enzymes involved in the breakdown of the aromatic ring. In addition, the appearance of p-xylene-negative strains was linked with a significant fall in the specific activity of all enzymes, except pyrocatechuase, which was replaced by metapyrocatechuase on a number of substrates.
mesh_terms: D015109:4-Hydroxybenzoate-3-Monooxygenase / Q000378:metabolism; D002396:Catechols / Q000378:metabolism; D003408:Cresols / Q000378:metabolism; D014644:Genetic Variation; D006899:Mixed Function Oxygenases / Q000378:metabolism; D011520:Protocatechuate-3,4-Dioxygenase / Q000378:metabolism; D011550:Pseudomonas aeruginosa / Q000201:enzymology*; D014992:Xylenes / Q000378:metabolism*
chemical_list: D002396:Catechols; D003408:Cresols; D014992:Xylenes; D006899:Mixed Function Oxygenases; D011520:Protocatechuate-3,4-Dioxygenase; C019947:p-cresol oxidoreductase; D015109:4-Hydroxybenzoate-3-Monooxygenase; C026267:4-xylene methylhydroxylase