Characterization of pyranose oxidase variants for bioelectrocatalytic applications

Issue Date

11-2019

Abstract

Pyranose oxidase (POx) catalyzes the oxidation of D-glucose to 2-ketoglucose with concurrent reduction of oxygen to H2O2. POx from Trametes ochracea (ToPOx) is known to react with alternative electron acceptors including 1,4-benzoquinone (1,4-BQ), 2,6-dichlorophenol indophenol (DCPIP), and the ferrocenium ion. In this study, enzyme variants with improved electron acceptor turnover and reduced oxygen turnover were characterized as potential anode biocatalysts. Pre-steady-state kinetics of the oxidative half-reaction of ToPOx variants T166R, Q448H, L545C, and L547R with these alternative electron acceptors were evaluated using stopped-flow spectrophotometry. Higher kinetic constants were observed as compared to the wild-type ToPOx for some of the variants. Subsequently, the variants were immobilized on glassy carbon electrodes. Cyclic voltammetry measurements were performed to measure the electrochemical responses of these variants with glucose as substrate in the presence of 1,4-BQ, DCPIP, or ferrocene methanol as redox mediators. High catalytic efficiencies (Imaxapp/KMapp) compared to the wild-type POx proved the potential of these variants for future bioelectrocatalytic applications, in biosensors or biofuel cells. Among the variants, L545C showed the most desirable properties as determined kinetically and electrochemically.

Source or Periodical Title

Biochimica et Biophysica Acta - Proteins and Proteomics

ISSN

1570-9639

Volume

1868

Issue

2

Page

1-9

Document Type

Article

Physical Description

illustration, graphs, tables; references

Language

English

Subject

Bioelectrocatalysis, Biofuel cells, GMC oxidoreductase, Oxidative half-reaction, Pyranose oxidase

Identifier

10.1016/j.bbapap.2019.140335.

Digital Copy

yes

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