%0 Journal Article
%T Pyranose Dehydrogenase from Agaricus campestris and Agaricus xanthoderma: Characterization and Applications in Carbohydrate Conversions
%A Petra Staudigl
%A Iris Krondorfer
%A Dietmar Haltrich
%A Clemens K. Peterbauer
%J Biomolecules
%D 2013
%I MDPI AG
%R 10.3390/biom3030535
%X Pyranose dehydrogenase (PDH) is a flavin-dependent sugar oxidoreductase that is limited to a rather small group of litter-degrading basidiomycetes. The enzyme is unable to utilize oxygen as an electron acceptor, using substituted benzoquinones and (organo) metal ions instead. PDH displays a broad substrate specificity and intriguing variations in regioselectivity, depending on substrate, enzyme source and reaction conditions. In contrast to the related enzyme pyranose 2-oxidase (POx), PDHs from several sources are capable of oxidizing ¦Á- or ¦Â-1¡ú4-linked di- and oligosaccharides, including lactose. PDH from A. xanthoderma is able to perform C-1 and C-2 oxidation, producing, in addition to lactobionic acid, 2-dehydrolactose, an intermediate for the production of lactulose, whereas PDH from A. campestris oxidizes lactose nearly exclusively at the C-1 position. In this work, we present the isolation of PDH-encoding genes from A. campestris (Ac) and A. xanthoderma (Ax) and a comparison of other so far isolated PDH-sequences. Secretory overexpression of both enzymes in Pichia pastoris was successful when using their native signal sequences with yields of 371 U¡¤L £¿1 for AxPDH and 35 U¡¤L £¿1 for AcPDH. The pure enzymes were characterized biochemically and tested for applications in carbohydrate conversion reactions of industrial relevance.
%K pyranose dehydrogenase
%K heterologous expression
%K agaricus
%K lactose conversion
%K lactobionic acid
%U http://www.mdpi.com/2218-273X/3/3/535