[Characteristics of the key enzyme regulation of peripheral p-xylene metabolism in Pseudomonas aeruginosa].

The regulation of p-xylene methylhydroxylase, metapyrocatechase, pyrocatechase and protocatechoate-3,4-dioxygenase was studied in Pseudomonas aeruginosa 2x. Methylhydroxylase, the first enzyme of p-xylene oxidation, was shown to be synthesized in the strain in a constitutive manner and to be regulated at the level of the enzyme activity. Metapyrocatechase, protocatechase and pyrocatechase are inducible enzymes; these are repressed to a different extent by the end products of p-xylene oxidation. Metapyrocatechase has a broader substrate specificity as compared to pyrocatechase and is induced by a greater number of substrates, the affinity for different substrates depending on the structure of an inductor. Presumably, two isofunctional metapyrocatechases exist in P. aeruginosa 2 x.