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Phenol Hydroxylase and Toluene/ o -Xylene Monooxygenase from Pseudomonas stutzeri OX1: Interplay between Two Enzymes
- Source :
- Applied and Environmental Microbiology. 70:2211-2219
- Publication Year :
- 2004
- Publisher :
- American Society for Microbiology, 2004.
-
Abstract
- Degradation of aromatic hydrocarbons by aerobic bacteria is generally divided into an upper pathway, which produces dihydroxylated aromatic intermediates by the action of monooxygenases, and a lower pathway, which processes these intermediates down to molecules that enter the citric acid cycle. Bacterial multicomponent monooxygenases (BMMs) are a family of enzymes divided into six distinct groups. Most bacterial genomes code for only one BMM, but a few cases (3 out of 31) of genomes coding for more than a single monooxygenase have been found. One such case is the genome of Pseudomonas stutzeri OX1, in which two different monooxygenases have been found, phenol hydroxylase (PH) and toluene/ o -xylene monooxygenase (ToMO). We have already demonstrated that ToMO is an oligomeric protein whose subunits transfer electrons from NADH to oxygen, which is eventually incorporated into the aromatic substrate. However, no molecular data are available on the structure and on the mechanism of action of PH. To understand the metabolic significance of the association of two similar enzymatic activities in the same microorganism, we expressed and characterized this novel phenol hydroxylase. Our data indicate that the PH P component of PH transfers electrons from NADH to a subcomplex endowed with hydroxylase activity. Moreover, a regulatory function can be suggested for subunit PH M. Data on the specificity and the kinetic constants of ToMO and PH strongly support the hypothesis that coupling between the two enzymatic systems optimizes the use of nonhydroxylated aromatic molecules by the draining effect of PH on the product(s) of oxidation catalyzed by ToMO, thus avoiding phenol accumulation.
- Subjects :
- phenol hydroxylase
DNA, Bacterial
Aerobic bacteria
Stereochemistry
Molecular Sequence Data
toluene o-xylene monooxygenase
Hydrocarbons, Aromatic
Applied Microbiology and Biotechnology
Mixed Function Oxygenases
Substrate Specificity
chemistry.chemical_compound
Multienzyme Complexes
Pseudomonas
Phenol
Enzymology and Protein Engineering
Pseudomonas stutzeri
chemistry.chemical_classification
Base Sequence
Ecology
biology
o-Xylene
Monooxygenase
biology.organism_classification
Toluene
Recombinant Proteins
Kinetics
Protein Subunits
Biodegradation, Environmental
Enzyme
Biochemistry
chemistry
Genes, Bacterial
Oxygenases
Food Science
Biotechnology
Subjects
Details
- ISSN :
- 10985336 and 00992240
- Volume :
- 70
- Database :
- OpenAIRE
- Journal :
- Applied and Environmental Microbiology
- Accession number :
- edsair.doi.dedup.....084755e16b139b81214b88acf41a3021