Purification of hydroxyquinol 1,2-dioxygenase and maleylacetate reductase: the lower pathway of 2,4,5-trichlorophenoxyacetic acid metabolism by Burkholderia cepacia AC1100.
The enzyme hydroxyquinol 1,2-dioxygenase, which catalyzes ortho cleavage of hydroxyquinol (1,2,4-trihydroxybenzene) to produce maleylacetate, was purified from Escherichia coli cells containing the tftH gene from Burkholderia cepacia AC1100. Reduction of the double bond in maleylacetate is catalyzed by the enzyme maleylacetate reductase, which was also purified from E. coli cells, these cells containing the tftE gene from B. cepacia AC1100. The two enzymes together catalyzed the conversion of hydroxyquinol to 3-oxoadipate. The purified hydroxyquinol 1,2-dioxygenase was specific for hydroxyquinol and was not able to use catechol, tetrahydroxybenzene, 6-chlorohydroxyquinol, or 5-chlorohydroxyquinol as its substrate. The native molecular mass of hydroxyquinol 1,2-dioxygenase was 68 kDa, and the subunit size of the protein was 36 kDa, suggesting a dimeric protein of identical subunits.
Department of Microbiology and Immunology, College of Medicine, University of Illinois at Chicago 60612, USA.
D L
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Daubaras
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Saido
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Chakrabarty
D015085:2,4,5-Trichlorophenoxyacetic Acid / Q000378:metabolism*; D001673:Biodegradation, Environmental; D016956:Burkholderia cepacia / Q000201:enzymology* / Q000235:genetics / Q000378:metabolism; D049308:Dioxygenases; D004926:Escherichia coli / Q000235:genetics; D005798:Genes, Bacterial; D007700:Kinetics; D008970:Molecular Weight; D010088:Oxidoreductases / Q000235:genetics / Q000302:isolation & purification* / Q000378:metabolism; D044925:Oxidoreductases Acting on CH-CH Group Donors; D010105:Oxygenases / Q000235:genetics / Q000302:isolation & purification* / Q000378:metabolism; D011487:Protein Conformation; D011994:Recombinant Proteins / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism; D013379:Substrate Specificity
D011994:Recombinant Proteins; D015085:2,4,5-Trichlorophenoxyacetic Acid; D010088:Oxidoreductases; D010105:Oxygenases; D049308:Dioxygenases; C041894:hydroxyquinol 1,2-dioxygenase; D044925:Oxidoreductases Acting on CH-CH Group Donors; C021530:maleylacetate reductase