Aspergillus niger, glucose oxidase enzyme from

In redox reactions, isolated oxidative enzymes such as laccase C from Trametes and horseradish/soybean peroxidases (with mediators) have been shown to possess good catalytic activity in common ILs on syringaldizine and veratryl alcohol, respectively [35]. Recently, oxidase-peroxidase-catalyzed chemo- and stereoselective sulfoxidations of thioanisole and methyl-2-naphthyl sulfide have been successfully carried out with a system of Coprinus cinereus (CiP) peroxidase and Aspergillus niger glucose oxidase (GOD) in 10% water in [BMIM][PF6] (Scheme 2). An enantiomeric... 

Enzyme sensors for carbohydrates. An enzyme electrode for glucose was the first electrochemical biosensor studied [1] and since then intensive research has taken place, providing new ideas and experiences for the development of other biosensors. Glucose biosensors usually use as a biological component the relatively stable enzyme glucose oxidase, preferably from Aspergillus niger (Fig. 14). This enzyme may serve as a model for all flavin oxidoreductases which can be applied not only for... 

Enzyme labels are usually coupled to secondary antibodies or to (strept)avidin. The latter is used for detection of biotinylated primary or secondary antibodies in ABC methods (see Sect. 6.2.1). Enzyme labels routinely used in immunohisto-chemistry are horseradish peroxidase (HRP) and calf intestinal alkaline phosphatase (AP). Glucose oxidase from Aspergillus niger and E. coli (3-galactosidase are only rarely applied. 

Glucose oxidase is obtained from molds such as Aspergillus niger and species of Penicillium, In its gross molecular properties at least, the enzyme from A. niger resembles l- rather than n-amino acid oxidase (19) since it is a dimer of 186,000 MW with two tightly, but noncovalently, bound FAD molecules per dimer. These FAD moieties are kinetically independent and probably, therefore, are present at an active site on each subunit. The enzyme is remarkably stable over a wide range of pH and other variables, which makes it ideal for analytical and bulk conversion applications. 

A purified D-glucose oxidase (mol. wt. 1.6 x 10 ) from Aspergillus niger contains two atoms of iron, flavin adenine dinucleotide, neutral sugars (16.4%), and 2-amino-2-deoxyhexoses (2.4 %). The holoenzyme is composed of two identical subunits (mol. wt. 7.9 x lO ) that have the same molecular weight as the apo-enzyme. Flavin hypoxanthine dinucleotide is as effective a coenzyme as flavin adenine dinucleotide. 

In a study of the periodate oxidation of r>-glucose oxidase from Aspergillus niger, 50% of the carbohydrate was removed with little effect on enzymic activity. Gel permeation chromatography results suggested that the oxidized enzyme exists as a complex oligomerizing system. 

D-Glucose Oxidase.— The carbohydrate moieties of D-glucose oxidase from Aspergillus niger have been modified by oxidation with periodate ion. Although ca. 60% of the carbohydrate residues were oxidized at pH 5.6, none of the amino-acid residues was oxidized. The oxidized enzyme retained its full activity and was converted into an immobilized form. 

To avoid interference with the active site of the enzyme, D-glucose oxidase from Aspergillus niger has been immobilized by way of its carbohydrate moieties. Thus, treatment of the periodate-oxidized enzyme with a styrene derivative afforded a water-insoluble material retaining full enzymic activity and exhibiting enhanced thermal stability at 60 °C. 

The D-glucose oxidase from Aspergillus niger binds concanavalin A to form an enzymically active precipitate, which is dissociated by methyl a-D-gluco-pyranoside. The adsorption, desorption, and activity of this D-glucose oxidase on selected clays followed the pattern exhibited by other proteins, with maximum adsorption onto the clay occurring at, or below, the isoelectric point. ... 

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