Screening of basidiomycete fungi for the quinone-dependent sugar C-2/C-3 oxidoreductase, pyranose dehydrogenase, and properties of the enzyme from Macrolepiota rhacodes

Citation
J. Volc et al., Screening of basidiomycete fungi for the quinone-dependent sugar C-2/C-3 oxidoreductase, pyranose dehydrogenase, and properties of the enzyme from Macrolepiota rhacodes, ARCH MICROB, 176(3), 2001, pp. 178-186
Citations number
23
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Microbiology
Journal title
ARCHIVES OF MICROBIOLOGY
ISSN journal
0302-8933 → ACNP
Volume
176
Issue
3
Year of publication
2001
Pages
178 - 186
Database
ISI
SICI code
0302-8933(200109)176:3<178:SOBFFT>2.0.ZU;2-D
Abstract
Mycelial cultures of 76 strains of lignocellulose-degrading basidiomycete f ungi were screened for the activity of pyranose dehydrogenase, a novel suga r oxidoreductase recently detected in Agaricus bisporus. Of these fungi, 37 strains belonging to seven phylogenetically related genera of mostly litte r-decomposing Agaricales were positive for the dehydrogenase, based on acti vity assays towards D-glucose with 1,4-benzoquinone or ferricenium ion as e lectron acceptors, and on TLC/HPLC analyses of the reaction products. Lack of activity with O-2 as the oxidant, specificity for C-3 of D-glucose, and active extracellular secretion of the enzyme were used as criteria to diffe rentiate pyranose dehydrogenase from pyranose 2-oxidase (EC 1.1.3.10), know n to be produced by numerous wood-rotting fungi. Extracellular pyranose deh ydrogenase from Macrolepiota rhacodes was heavily glycosylated. The enzyme was characterized as a 78-kDa flavoprotein under denaturing conditions and a 76-kDa native protein using gel filtration. This enzyme had a maximum ext racellular activity of 4.1 U ml(-1) in 39-day liquid cultures. It exhibited broad selectivity for sugar substrates and oxidized D-glucose (K-m=1.82) e xclusively at C-3 to 3-dehydro-D-glucose (D-ribo-hexos-3-ulose), in contras t to pyranose dehydrogenases from Agaricus species, which acted at both C-3 and C-2 of D-glucose. The N-terminal sequence, AVVYRHPDEL, showed signific ant similarity with that reported for A. bisporus.