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

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 M_r values of 69 000 and 99 000 for pyranose oxidase and pyranosone dehydratase, respectively. The apparent M_r'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 -pyrone, cortalcerone. The latter compound was isolated as a diphenylhydrazone derivative and spectroscopically identified.Abbreviations DMAB 3-dimethylaminobenzoic acid - FPLC fast protein liquid chromatography - MBTH 3-methyl-2-benzothiazolinone hydrazone hydrochloride - PD pyranosone dehydratase - PMSF phenylmethylsulfonyl fluoride - POD pyranose oxidase