High activity catechol 2,3-dioxygenase from the cresols - Degrading Stenotrophomonas maltophilia strain KB2 |
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Authors: | Danuta Wojcieszy��skaKatarzyna Hupert-Kocurek Izabela Gre��Urszula Guzik |
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Affiliation: | Department of Biochemistry, Faculty of Biology and Environment Protection, University of Silesia, Jagiellonska 28, 40-032 Katowice, Poland |
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Abstract: | This study aimed at characterization of catechol 2,3-dioxygenase from Stenotrophomonas maltophilia KB2, being able to utilize a wide spectrum of aromatic substrates as a sole carbon and energy source. 2-methylphenol, 3-methylphenol, and 4-methylphenol was completely degraded during 24 h in concentration 6 mM, 7 mM, and 5 mM, respectively. When cells of strain KB2 were growing on methylphenols, catechol 2,3-dioxygenase was induced. Biochemical analysis revealed that the examined enzyme was similar to another catechol 2,3-dioxygenases, but showed extremely high activity. The enzyme was optimally active at 30 °C and pH 7.6. Kinetic studies showed that the value of Km, Vmax and Hill constant was 85.11 ??M, 3.08 ??M min−1 and 4.09 respectively. Comparative structural and phylogenetic analysis of catechol 2,3-dioxygenase from S. maltophilia KB2 had placed the protein with the single-ring substrate subfamily of the extradiol dioxygenase. We observed the presence of externally located ??-helices and internally located ??-sheets. We also suggest that the Fe2+ ion binding is facilitated via four ligands: two histidine residues, one glutamate residue and one molecule of water. |
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Keywords: | Biodegradation Stenotrophomonas Aromatic compounds Dioxygenases |
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