Pyranose oxidase and pyranosone dehydratase: enzymes responsible for conversion of d-glucose to cortalcerone by the basidiomycete Phanerochaete chrysosporium

Abstract

Pyranose oxidase (glucose 2-oxidase) and pyranosone dehydratase were purified 27.6- and 43.9-fold respectively from mycelial extracts of the fungus Phanerochaete chrysosporium using hydrophobic interaction, anion exchange and gel filtration chromatography. The enzymes appeared substantially homogeneous on SDS-PAGE and were comprised of identical subuntis with apparent Mr values of 69 000 and 99 000 for pyranose oxidase and pyranosone dehydratase, respectively. The apparent Mr's of the native enzymes, based on equilibrium ultracentrifugation, were 308 000 and 221 000. In coupled reactions, the enzymes catalyzed conversion of d-glucose via d-glucosone (d-arabino-2-hexosulose) to the antibiotic β-pyrone, cortalcerone. The latter compound was isolated as a diphenylhydrazone derivative and spectroscopically identified.