The glucose oxidase enzyme (GOx) binds to beta-D-glucose (an isomer of the six-carbon sugar glucose) and aids in breaking the sugar down into its metabolites. GOx is a dimeric protein (605aa; ~160Kd with one tightly bound FAD per monomer, K=1x10-10). Gox is glycosylated with a carbohydrate content of 16% (w/w). The carbohydrate moiety is designated as high mannose type with 80% (w/w) of the carbohydrate being mannose. The mannose is N and O glycosidically linked to Asn, Thr and Ser. The protein is readily soluble in 0.1M potassium phosphate pH 7.0 giving a clear, yellow solution. The molar extinction coefficient of a 1% (w/v) solution at 280nm is 13.8. The enzyme shows a very high degree of specificity for b-D-glucose although 2-deoxy-D- glucose, D-mannose and D-fructose are also oxidised, albeit at a much reduced rate. The native protein is acidic having an isoelectric point (pI) of 4.2. GOx catalyzes the oxidation of beta-D-glucose into D- glucono-1,5-lactone, which then hydrolyzes to gluconic acid. In order to work as a catalyst, GOx requires a cofactor, flavin adenine dinucleotide (FAD). FAD is a common component in biological oxidation-reduction (redox reactions). Redox reactions involve a gain or loss of electrons from a molecule. In the GOx-catalyzed redox reaction, FAD works as the initial electron acceptor and is reduced to FADH2. Then FADH2 is oxidized by the final electron acceptor, molecular oxygen (O2), which can do so because it has a higher reduction potential. O2 is then reduced to hydrogen peroxide (H2O2). The glucose oxidase enzyme is commonly used in biosensors to detect levels of glucose by keeping track of the number of electrons passed through the enzyme by connecting it to an electrode and measuring the resulting charge. When produced commercially for this application, it is often extracted from Aspergillus niger. Glucose oxidase is widely used for the determination of glucose in body fluids and in removing residual glucose and oxygen from beverages and foodstuffs. Furthermore, Glucose oxidase-producing moulds such as Aspergillus and Penicillum Species are used for the biological production of gluconic acid.
Source:Glucose Oxidase from Aspergillus niger
Molecular Weight:~160kD
Enzyme Activity:~300 units/mg protein or ~200 units/mg solid material, average 225-275.
Inhibitors:Ag+, Hg2+, Cu2+. FAD binding is inhibited by several nucleotides
Unit Definition:1 unit producing oxidation of 1 umole of glucose per minute at 25°C and pH 7.0. 1 unit is 0.6 units in the system below, but without oxygenation. 0.6 units using 4-AA-phenol coupled with HRP at pH 5.6 and 30°C. 0.63 titrimetric units at pH 5.1 and 35°C.
Solubility:Dissolve readily at 5mg/ml in 0.1M potassium phosphate, pH 7.0.
Storage and Stability:Store lyophilized powder dessicated at 20°C. Stable for 12 months at -20°C. For maximum recovery of product, centrifuge the original vial after thawing and prior to removing the cap. Further dilutions can be made in assay buffer. This product is sensitive to light.
仕様
Size：250mg
Source Antigen：Aspergillus niger
Form：Supplied as a lyophilized powder. No preservative added.
