Properties Of Glucose Oxidase Research Articles

APPLICATION OF NANOMATERIALS (SPECIALLY STRUCTURED GRAPHITE AND GOLD NANOPARTICLES) IN EXPRESS-DIAGNOSTICS OF GLUCOSE CONCENTRATION IN BLOOD

Samples of nanomaterials were obtained: nanostructured graphite and gold nanoparticles. Their influence on the properties of glucose oxidase in the receptor layer of test strips for detecting glucose in blood was studied. It has been shown that the use of these nanomaterials makes it possible to increase the sensitivity and accuracy of measurements of glucose in solution and human blood, to shorten the response time, and to ensure the stability of the test strip parameters for 18 months.

Preparation and catalytic properties of glucose oxidase encapsulated in catalase-conjugated liposomes for effective oxidation of glucose

Preparation and catalytic properties of glucose oxidase encapsulated in catalase-conjugated liposomes for effective oxidation of glucose

Glucose oxidase: natural occurrence, function, properties and industrial applications

Glucose oxidase (GOX) from Aspergillus niger is a well-characterised glycoprotein consisting of two identical 80-kDa subunits with two FAD co-enzymes bound. Both the DNA sequence and protein structure at 1.9 A have been determined and reported previously. GOX catalyses the oxidation of D: -glucose (C(6)H(12)O(6)) to D: -gluconolactone (C(6)H(10)O(6)) and hydrogen peroxide. GOX is produced naturally in some fungi and insects where its catalytic product, hydrogen peroxide, acts as an anti-bacterial and anti-fungal agent. GOX is Generally Regarded As Safe, and GOX from A. niger is the basis of many industrial applications. GOX-catalysed reaction removes oxygen and generates hydrogen peroxide, a trait utilised in food preservation. GOX has also been used in baking, dry egg powder production, wine production, gluconic acid production, etc. Its electrochemical activity makes it an important component in glucose sensors and potentially in fuel cell applications. This paper will give a brief background on the natural occurrence, functions as well as the properties of glucose oxidase. A good coverage on the diverse uses of glucose oxidase in the industry is presented with a brief outline on the working principles in the various settings. Furthermore, food grade GOX preparations are relatively affordable and widely available; the readers may be encouraged to explore other potential uses of GOX. One example is that GOX-catalysed reaction generates significant amount of heat (~200 kJ/mol), and this property has been mostly neglected in the various applications described so far.

Glucose Oxidase as an Analytical Reagent

Abstract Glucose oxidase (EC 1.1.3.4) is the most widly employed enzyme as analytical reagent. This is the result of (1) its utility in the determination of glucose, an analyte of wide analytical interest, and (2) its relatively low cost and good stability that make the glucose/glucose oxidase system a very convenient model for method development (particularly in the area of biosensors). This review discusses in detail enzyme structure, biocatalysis, enzymes as analytical reagents, properties of glucose oxidase (including a historical account), and the use of glucose oxidase as an analytical reagent in homogeneous systems as well as an immobilized reagent.

Effect of enzyme ratio on the properties of glucose oxidase and catalase immobilized on modified perlite

Processed perlite modified by silanization and treatment with glutaraldehyde was used as a support for the co-immobilization of glucose oxidase and catalase. Immobilization was carried out with several enzyme ratios and activity investigated with respect to pH and temperature. The deactivation rates of the preparations were investigated in recycling fluid bed reactors.

New method for fabricating Langmuir-Blodgett films of water-soluble proteins with retained enzyme activity

A new method has been developed for fabricating monolayers of water-soluble proteins on a water surface and transferring the protein Langmuir-Blodgett (LB) films from the water surface. Monolayers of glucose oxidase (GOD) or cytochrome c(cyt- c) spread on 3 M (NH 4) 2SO 4 solution were transferred onto the water surface with a Fromherz LB trough. Two layers of GOD or cyt- c were transferred on each side of a hydrophobic glass plate from the water surface as Y-type layers. The properties of GOD and cyt- c on the water surface and the LB films were investigated. The GOD LB film exhibited enzyme activity. The new method seems feasible for fabricating LB films of water-soluble proteins.

Production, purification, and properties of glucose oxidase from the biocontrol fungus Talaromyces flavus

Talaromyces flavus produces the enzyme glucose oxidase, which may be involved in biocontrol of the fungal plant pathogen, Verticillium dahliae. A strain of T. flavus was selected from the wild-type population for the production of extracellular glucose oxidase, and the enzyme was purified by a combination of acetone precipitation and high performance liquid chromatography (HPLC). Approximately 12–25 mg of pure protein was obtained from 2 L of culture, and the total recovered activity ranged from 5 to 10 × 103 μmol/min. Homogeneity of the purified enzyme was demonstrated by HPLC and by native and sodium dodecylsulfate polyacrylamide gel electrophoresis. Molecular weight of the native enzyme was 164 000 and that of the subunit was71 000, which indicated that the native enzyme is a dimer. The apparent Km value for D-glucose was 10.9 mM. The optimum pH for the enzyme activity was 5.0, but the enzyme was stable in buffer from pH 3 to 7. The enzyme was observed to be a glycoprotein, and amino acid analysis of the purified enzyme indicated a similarity to glucose oxidases from fungal sources. Isozymes of the enzyme with pI values of 4.40–4.55 were detected on analytical isoelectric focusing gels. Key words: antibiosis, biocontrol, glucose oxidase, Talaromyces flavus.

Characterization and application of glucose oxidase immobilized in silica hydrogel

AbstractThe properties of glucose oxidase (EC1134) embedded in silica gel were investigated. The immobilized preparations retained 62% of the activity of the mobilized enzyme. The optimum pH value (5.8) and temperature (30°C) were the same for the immobilized as for the soluble enzyme, but immobilized glucose oxidase had higher thermal and pH‐stability. The constants of thermal and pH inactivation, and the Michaelis constants were calculated.The effects of various cations and proteins on the activity of the immobilized enzyme were studied; NH4, K+, Mg2+ and gelatin all increased the relative activity of the preparations to 93–96% of the soluble enzyme.Combined immobilized preparations of glucose oxidase and catalase were repeatedly used in the oxidation of D‐glucose and the preparation of calcium gluconate.

Effect of periodate oxidation on the structure and properties of glucose oxidase

In order to elucidate the molecular structure of glucose oxidase (β- d-glucose: oxygen 1-oxidoreductase, EC 1.1.3.4) and the roles of its carbohydrate moiety, chemical, physiochemical and immunological experiments were performed with enzyme samples before and after periodate oxidation. Hydrodynamic parameters indicated that the native enzyme was a globular protein with values of 1.21 for the frictional ratio and 43 Å for the Stokes radius. The enzyme contained about 12% carbohydrate by weight, of which the main component was mannose. The periodate treatment decreased the carbohydrate content to about 40% of its original value. Slight modifications were detected in the absorbance spectrum and the content of arginyl residue. However, no significant alteration was brought about by this treatment in the catalytic parameters, immunological reactivities or the gross structure, nor in the secondary and quaternary structures of the protein moiety. Thermal denaturation temperature (about 72.5°C) and the enthalpy of denaturation (about 450 kcal/mol) were common to the native and the periodate-oxidized enzymes. The native enzyme was found to be quite resistant to sodium dodecyl sulfate and fairly stable to urea and heating. The periodate-oxidized enzyme was also stable to heat treatment, but it showed a diminished stability when denaturing agents were present. Kinetic analyses of the thermal inactivation processes showed that the entropy of activation was greatly decreased by the denaturing agents, especially in the case of the periodate-oxidized enzyme. It is concluded that the carbohydrate moiety of the enzyme plays a role in increasing the stability of the protein moiety, but does not directly participate in the catalytic activity, in the immunological reactivity, or in maintaining the conformation of the enzyme protein.

Enzymatic Determinations of Glucose

Publisher Summary This chapter highlights that glucose is important in the metabolism of most cells—animal, plant, and microbe—and a number of enzymes have been identified which catalyze the reactions of glucose. It discusses that enzymatic methods have a number of theoretical advantages, and therefore, it is quite logical that much attention has been devoted to the subject of enzymatic determinations of glucose. In all instances, the theoretical advantages do not necessarily apply in the defined procedures. Early qualitative and quantitative tests in which yeast was employed for either the identification or measurement of glucose might be considered to have an enzymatic basis as the desired actions were accomplished by means of the enzymatic processes in living yeast cells. This chapter describes the history and properties of glucose oxidase. It presents an account of the utilization of glucose oxidase for the measurement of glucose in urine and blood, and for other test situations that may be of interest in clinical chemistry.