Publication: The substrate oxidation mechanism of pyranose 2-oxidase and other related enzymes in the glucose-methanol-choline superfamily
Issued Date
2013-07-01
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ISSN
17424658
1742464X
1742464X
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2-s2.0-84879230778
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Mahidol University
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SCOPUS
Bibliographic Citation
FEBS Journal. Vol.280, No.13 (2013), 3009-3027
Suggested Citation
Thanyaporn Wongnate, Pimchai Chaiyen The substrate oxidation mechanism of pyranose 2-oxidase and other related enzymes in the glucose-methanol-choline superfamily. FEBS Journal. Vol.280, No.13 (2013), 3009-3027. doi:10.1111/febs.12280 Retrieved from: https://repository.li.mahidol.ac.th/handle/123456789/31281
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Title
The substrate oxidation mechanism of pyranose 2-oxidase and other related enzymes in the glucose-methanol-choline superfamily
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Abstract
Enzymes in the glucose-methanol-choline (GMC) oxidoreductase superfamily catalyze the oxidation of an alcohol moiety to the corresponding aldehyde. In this review, the current understanding of the sugar oxidation mechanism in the reaction of pyranose 2-oxidase (P2O) is highlighted and compared with that of other enzymes in the GMC family for which structural and mechanistic information is available, including glucose oxidase, choline oxidase, cholesterol oxidase, cellobiose dehydrogenase, aryl-alcohol oxidase, and pyridoxine 4-oxidase. Other enzymes in the family that have been newly discovered or for which less information is available are also discussed. A large primary kinetic isotope effect was observed for the flavin reduction when 2-d-d-glucose was used as a substrate, but no solvent kinetic isotope effect was detected for the flavin reduction step. The reaction of P2O is consistent with a hydride transfer mechanism in which there is stepwise formation of d-glucose alkoxide prior to the hydride transfer. Site-directed mutagenesis of P2O and pH-dependence studies indicated that His548 is a catalytic base that facilitates the deprotonation of C2-OH in d-glucose. This finding agrees with the current mechanistic model for aryl-alcohol oxidase, glucose oxidase, cellobiose dehydrogenase, methanol oxidase, and pyridoxine 4-oxidase, but is different from that of cholesterol oxidase and choline oxidase. Although all of the GMC enzymes share similar structural folding and use the hydride transfer mechanism for flavin reduction, they appear to have subtle differences in the fine-tuned details of how they catalyze substrate oxidation. This review surveys recent discoveries about the reaction mechanisms of pyranose 2-oxidase and other members of the glucose-methanol-choline (GMC) oxidoreductase superfamily. These enzymes are flavoenzymes that catalyze the oxidation of alcohol moiety to aldehyde. Most current research finds that GMC enzymes use the hydride transfer mechanism, but the modes by which substrates are activated to facilitate the hydride transfer reaction appear to differ. © 2013 FEBS.