title: Observation of superoxide production during catalysis of Bacillus subtilis oxalate decarboxylase at pH 4.
abstract: This contribution describes the trapping of the hydroperoxyl radical at a pH of 4 during turnover of wild-type oxalate decarboxylase and its T165V mutant using the spin-trap BMPO. Radicals were detected and identified by a combination of EPR and mass spectrometry. Superoxide, or its conjugate acid, the hydroperoxyl radical, is expected as an intermediate in the decarboxylation and oxidation reactions of the oxalate monoanion, both of which are promoted by oxalate decarboxylase. Another intermediate, the carbon dioxide radical anion was also observed. The quantitative yields of superoxide trapping are similar in the wild type and the mutant while it is significantly different for the trapping of the carbon dioxide radical anion. This suggests that the two radicals are released from different sites of the protein.
authors.affiliation: Department of Chemistry, University of Florida, Gainesville, FL 32611-7200, USA.
authors.forename: Umar T
authors.initials: UT
authors.lastname: Twahir
authors.affiliation: Department of Chemistry, University of Florida, Gainesville, FL 32611-7200, USA.
authors.forename: Corey N
authors.initials: CN
authors.lastname: Stedwell
authors.affiliation: Department of Chemistry, University of Florida, Gainesville, FL 32611-7200, USA.
authors.forename: Cory T
authors.initials: CT
authors.lastname: Lee
authors.affiliation: Department of Chemistry & Chemical Biology, Indiana University Purdue University, Indianapolis, Indianapolis, IN 46202, USA.
authors.forename: Nigel G J
authors.initials: NG
authors.lastname: Richards
authors.affiliation: Department of Chemistry, University of Florida, Gainesville, FL 32611-7200, USA.
authors.forename: Nicolas C
authors.initials: NC
authors.lastname: Polfer
authors.affiliation: Department of Chemistry, University of Florida, Gainesville, FL 32611-7200, USA. Electronic address: alex@chem.ufl.edu.
authors.forename: Alexander
authors.initials: A
authors.lastname: Angerhofer
mesh_terms: D001412:Bacillus subtilis / Q000737:chemistry* / Q000201:enzymology; D001426:Bacterial Proteins / Q000737:chemistry* / Q000235:genetics; D002245:Carbon Dioxide / Q000737:chemistry; D002262:Carboxy-Lyases / Q000737:chemistry* / Q000235:genetics; D003497:Cyclic N-Oxides; D004578:Electron Spin Resonance Spectroscopy; D006863:Hydrogen-Ion Concentration; D009154:Mutation; D010070:Oxalates / Q000737:chemistry; D010084:Oxidation-Reduction; D011993:Recombinant Fusion Proteins / Q000737:chemistry* / Q000235:genetics; D013113:Spin Labels; D019097:Spin Trapping; D013481:Superoxides / Q000737:chemistry*
chemical_list: C441196:5-tert-butoxycarbonyl 5-methyl-1-pyrroline N-oxide; D001426:Bacterial Proteins; D003497:Cyclic N-Oxides; D010070:Oxalates; D011993:Recombinant Fusion Proteins; D013113:Spin Labels; D013481:Superoxides; D002245:Carbon Dioxide; D002262:Carboxy-Lyases; C021915:oxalate decarboxylase
keywords: BMPO; Carbon dioxide radical; Oxalate decarboxylase; Spin trapping; Superoxide