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Resolution, purification and some properties of the multiple forms of cellobiose quinone dehydrogenase from the white-rot fungus Sporotrichum pulverulentum.

ABSTRACT: Four forms of cellobiose quinone dehydrogenase have been purified from the white-rot fungus Sporotrichum pulverulentum. The Mr of the enzyme has been estimated by sedimentation equilibrium to be 57,800 and by SDS/polyacrylamide-gel to be 60,000. These enzymes are clearly monomers. Cellobiose quinone dehydrogenases contain FAD and variable amounts of a green chromophore which we suggest is 6-hydroxy-FAD. The superoxide anion and H2O2 are the products of its reaction with oxygen. All of the isoenzymes from any one preparation display similar kinetic parameters. However, these vary between preparations. The only apparent difference between the four separable isoenzymes is their neutral-sugar content.

SUBMITTER: Morpeth FF

PROVIDER: S-EPMC1146809 | biostudies-other | 1986 May

REPOSITORIES: biostudies-other

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Some properties of cellobiose oxidase from the white-rot fungus Sporotrichum pulverulentum.

Project description:Cellobiose oxidase from the white-rot fungus Sporotrichum pulverulentum has been purified to homogeneity by a new procedure. The carbohydrate and amino acid compositions of the enzyme have been determined. Cellobiose oxidase contains FAD and cytochrome b prosthetic groups. Mr of the enzyme has been estimated at 74400 by sedimentation equilibrium. The enzyme is a monomer. Optical, fluorescence and e.p.r. spectra of oxidized and reduced cellobiose oxidase have been determined. A preliminary investigation of the substrate specificity of cellobiose oxidase reveals that disaccharides and even some insoluble polysaccharides are substrates, but not monosaccharides. Strong substrate inhibition is seen at high concentrations of cellobiose. This effect is particularly marked when oxygen is the electron acceptor. Cellobiose oxidase is unusual among flavoproteins, since it stabilizes the red anionic flavin semiquinone and forms a sulphite adduct, yet appears to produce the superoxide anion as its primary reduced oxygen product.

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