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Article
Real-time Kinetic Studies of Bacillus Subtilis Oxalate Decarboxylase and Ceriporiopsis Subvermispora Oxalate Oxidase Using Luminescent Oxygen Sensor
Journal of Biochemical Technology
  • Laura Molina, University of Florida
  • Thomas Goodall, University of Florida
  • Umar Twahir, University of Florida
  • Ellen W. Moomaw, Kennesaw State University
Department
Chemistry & Biochemistry
Document Type
Article
Publication Date
12-25-2014
Disciplines
Abstract

Oxalate decarboxylase (OxDC), an enzyme of the bicupin superfamily, catalyzes the decomposition of oxalate into carbon dioxide and formate at an optimal pH of 4.3 in the presence of oxygen. However, about 0.2% of all reactions occur through an oxidase mechanism that consumes oxygen while producing two equivalents of carbon dioxide and one equivalent of hydrogen peroxide. The kinetics of oxidase activity were studied by measuring the consumption of dissolved oxygen over time using a luminescent oxygen sensor. We describe the implementation of and improvements to the oxygen consumption assay. The oxidase activity of wild type OxDC was compared to that of the T165V OxDC mutant, which contains an impaired flexible loop covering the active site. The effects of various carboxylic acid-based buffers on the rate of oxidase activity were also studied. These results were compared to the oxidase activity of oxalate oxidase (OxOx), a similar bicupin enzyme that only carries out oxalate oxidation. The temperature dependence of oxidase activity was analyzed, and preliminary results offer an estimate for the overall activation energy of the oxidase reaction within OxDC. The data reported here thus provide insights into the mechanism of the oxidase activity of OxDC.

Citation Information
Laura Molina, Thomas Goodall, Umar Twahir and Ellen W. Moomaw. "Real-time Kinetic Studies of Bacillus Subtilis Oxalate Decarboxylase and Ceriporiopsis Subvermispora Oxalate Oxidase Using Luminescent Oxygen Sensor" Journal of Biochemical Technology Vol. 5 Iss. 4 (2014) p. 826 - 831 ISSN: 0974-2328
Available at: http://works.bepress.com/ellen-moomaw/14/