Related Experiment Videos
3,4-Dihydroxyxanthone dioxygenase from Arthrobacter sp. strain GFB100
1Department of Food Science, Cook College, New Jersey Agricultural Experiment Station, Rutgers University, New Brunswick 08903.
Applied and Environmental Microbiology
|August 1, 1991
Summary
Bacterial 3,4-dihydroxyxanthone dioxygenase (DHXD) from Arthrobacter sp. strain GFB100 transforms xanthone. This cytosolic enzyme requires Fe2+ and is stable at low temperatures, aiding biodegradation efforts.
Area of Science:
- Microbiology
- Enzymology
- Biochemistry
Background:
- Bacterial extradiol ring-fission dioxygenases are key in biodegrading complex aromatic compounds.
- Arthrobacter sp. strain GFB100 uses 3,4-dihydroxyxanthone dioxygenase (DHXD) for xanthone catabolism.
Purpose of the Study:
- To investigate the properties and activity of DHXD from Arthrobacter sp. strain GFB100.
- To understand the role of DHXD in the biodegradation of xanthone.
Main Methods:
- Enzyme activity assays were performed under various conditions (pH, temperature, inhibitors).
- Enzyme stability was tested through thermal inactivation and freeze-thaw cycles.
- Kinetic parameters, including Km and Ki, were determined.
Main Results:
- DHXD is a cytosolic enzyme, induced by xanthone and expressed during the stationary phase.
- Enzyme activity requires Fe2+ ions and is inhibited by 1,10-phenanthroline and H2O2.
- Optimal activity at 30°C and pH 7.0, with a Km of 10 μM for 3,4-dihydroxyxanthone.
- DHXD is thermally labile above 40°C but stable after freeze-thaw cycles and at 0°C.
Conclusions:
- DHXD is a crucial enzyme in xanthone biodegradation by Arthrobacter sp. strain GFB100.
- Its stability at low temperatures suggests potential for practical applications in bioremediation.
- The Fe2+ cofactor appears tightly bound, contributing to enzyme stability.