Purification and Characterization of Catechol 1,2-Dioxygenases from Rhodococcus rhodnii Strain 135 and Rhodococcus rhodochrous Strain 89: Comparison with Analogous Enzymes of an Ordinary and Modified ortho-Cleavage Pathways

摘要

Two grampositive strains, Rhodococcus rhodnii 135 and Rhodococcus rhodochrous 89, used phenol as sole source of carbon and enery. Degradation takes place via an ordinary ortho-cleavage pathway with catechol as a central intermediate. Both strains were able to transform a number of chlorinated and fluorinated phenols. Enzymes of the ordinary ortho-cleavage pathway carried out these reactions. The induction of the enzymes of a modified orthocleavage pathway did not occur. Catechol 1,2-dioxygenases purified from both strains were homodimers with subunit molecular weight 37 kDa. The velocity of the oxidation of monomethylcatechols was 1.3-1.6-fold higher than that of unsubstituted substrate. Both enzymes were characterized by relatively high activity with 3-chlorocatechol.