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

• Published in: Archives of microbiology Vol. 176; no. 3; pp. 178 - 186
• Main Authors: Volc, J, Kubatova, E, Daniel, G, Sedmera, P, Haltrich, D
• Format: Journal Article
• Language: English
• Published: Heidelberg Springer 01.09.2001; Berlin
• Subjects: Agaricus bisporus; Bacteriology; Basidiomycetes; Basidiomycota - enzymology; Basidiomycota - growth & development; Benzoquinones - metabolism; Biological and medical sciences; Carbohydrate Dehydrogenases - analysis; Carbohydrate Dehydrogenases - chemistry; Carbohydrate Dehydrogenases - metabolism; Carbohydrate Metabolism; Cellulose - metabolism; flavoproteins; Flavoproteins - analysis; Flavoproteins - chemistry; Flavoproteins - metabolism; Fundamental and applied biological sciences. Psychology; fungi; gel chromatography; glucose; Glucose - metabolism; glycosylation; Growth, nutrition, metabolism, transports, enzymes. Molecular biology; high performance liquid chromatography; Kinetics; Lignin - metabolism; Macrolepiota; Macrolepiota rhacodes; Metabolism. Enzymes; Microbiology; Molecular Weight; mycelium; Mycology; oxidants; oxidoreductase; Oxidoreductases - analysis; Oxidoreductases - chemistry; Oxidoreductases - metabolism; oxygen; phylogeny; Plant Roots - microbiology; pyranose dehydrogenase; screening; secretion; Agaricus bisporus; Enzyme; Quinone; Basidiomycetes; Lignocellulosics; Phylogeny; Dehydrogenase; Properties; Strain; Fungi; Screening; Carbohydrate; Oxidoreductases; Culture; Sugar; Thallophyta
• ISSN: 0302-8933; 1432-072X
• DOI: 10.1007/s002030100308

Mycelial cultures of 76 strains of lignocellulose-degrading basidiomycete fungi were screened for the activity of pyranose dehydrogenase, a novel sugar oxidoreductase recently detected in Agaricus bisporus. Of these fungi, 37 strains belonging to seven phylogenetically related genera of mostly litter-decomposing Agaricales were positive for the dehydrogenase, based on activity assays towards D-glucose with 1,4-benzoquinone or ferricenium ion as electron acceptors, and on TLC/HPLC analyses of the reaction products. Lack of activity with O2 as the oxidant, specificity for C-3 of D-glucose, and active extracellular secretion of the enzyme were used as criteria to differentiate pyranose dehydrogenase from pyranose 2-oxidase (EC 1.1.3.10), known to be produced by numerous wood-rotting fungi. Extracellular pyranose dehydrogenase 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 extracellular activity of 4.1 U ml-1 in 39-day liquid cultures. It exhibited broad selectivity for sugar substrates and oxidized D-glucose (Km=1.82) exclusively at C-3 to 3-dehydro-D-glucose (D-ribo-hexos-3-ulose), in contrast to pyranose dehydrogenases from Agaricus species, which acted at both C-3 and C-2 of D-glucose. The N-terminal sequence, AVVYRHPDEL, showed significant similarity with that reported for A. bisporus.