Glucose oxidase-catalase system

Experience shows that flow microcalorimetry is a universal technique that is suitable for the investigation of the catalytic properties of immobilized biocatalysts. This review has summarized all basic examples of its application, but has not exhausted all of their potential possibilities. As an example, the steady-state measurement of a bi-substrate enzyme reaction with a co-immobilized glucose oxidase-catalase system was reported [26]. However, there is no report on the evaluation of kinetic properties of partial enzymes in co-immobilized systems. Even the measurement of the overall heat produced in such systems does not provide direct information about partial reactions. We believe that new approaches to analyze these systems based on mathematical modeling can be developed. 

D-Glucose Oxidases.—D-Glucose oxidase, in combination with glucoamylase and D-gluconolactonase, has been used to convert maltose into D-gluconic acid. A study has been made of the efficiency of a o-glucose oxidase-catalase system, both with the free and immobilized enzymes. ... 

Two approaches are discussed for the preparation of enzymatically controlled drug delivery systems a calcium-responsive biodegradable drug delivery system based on a mixture of starch with HPMC (hydroxypropyl methyl cellulose ether) (biodegradable) and the starch hydrolytic enzyme, alpha-amylase, in its non-active form and a glucose responsive insulin delivery system based on the hydrogel poly(2-hydroxyethyl methacrylate-co-N,N-dimethylaminoethyl methacrylate), with entrapped glucose oxidase, catalase and insulin. In both systems, the sensitivity... 

Mixed immobilized enzyme systems of glucoamylase-D-glucose isomerase and D-glucose isomerase-D-glucose oxidase-catalase have been prepared and operated. Experimental results verified theoretical predictions that optimal bifunctional catalyst configurations could be superior to those where the catalysts were mixed uniformly or arranged sequentially in a tubular reactor. 

A proficient combination of responsiveness and enzjnne immobilization can lead to new sensitive materials. An illustrative example is provided by glucose-responsive polymer systems. Immobilization of glucose oxidase, catalase, and insulin into a pH-responsive polymer gel based on PDMAEMA led to glucose-responsive polymer systems. In the presence of glucose these small sugar molecules diffuse into the polymer gel. Srrbsequently, glucose oxidase catalyzes the oxidation of... 

In general, it is considered desirable to reduce the initiation reaction as a means of controlling peroxidation. Apart from anti-oxidants (BHT 3,5-di-t-butyl-4-hydrotoluene is often used as a food additive), metal binding compounds and phenolic compounds may be inhibitory as well as the superoxide dismutase and glucose oxidase-catalase enzyme systems. 

Figure SJ Activity of the various states of the [NiFe] hydrogenase from A. vinosum as determined with a Pt electrode at 30°C.The reaction was performed in SOmM Tris/HCI (pH 8.0) in a volume of 2 ml. Oxygen was scavenged by adding glucose (90 mM) and glucose oxidase (2.5 mg/ml). Hydrogen peroxide was removed by catalase. When the system was anaerobic, an aliquot of H2-saturated water was added, and a little later enzyme (S-IOnM) was injected. Benzyl viologen (4.2mM) was used as electron acceptor.

Reuss M, Buchholz K (1979) Analysis of the coupled transport, reaction and deactivation phenomena in the immobilized system glucose oxidase and catalase. Biotechnol Bioeng 21 2061-2081... 

Only in the coupled oxidation of nitrite using glucose oxidase-glucose- 0 (as H 0 0H generating system) and beef liver catalase, which results in the formation of isotopically enriched nitrate (183a), are the results compatible with an oxygen atom transfer mechanism [Eqs.(28) and (29) ]. Even in this case, alternative interpretations are possible, such as oxidation of nitrite via outer or inner sphere electron transfers [Eqs. 

In the glucose oxidase system, dissolved oxygen concentration as well as glucose levels will influence dehvery response requiring close control of mass-transfer limitations. For both systems containing a protein component, stabihty factors may limit operational hfetime. This may be particularly severe in the case of glucose oxidase where the reaction product H2O2 will accelerate enzyme denaturation unless it is rapidly removed by diffusion or reaction with a second enzyme (peroxidase or catalase). 

A miniaturized thermal flow-injection analysis biosensor was coupled with a microdialysis probe for continuous subcutaneous monitoring of glucose [34]. The system (Scheme 1) consisted of a miniaturized thermal biosensor with a small column containing co-immobilized glucose oxidase and catalase. The analysis buffer passed through the column at a flow rate of 60 pl/min via a 1-pl sample loop connected to a microdialysis probe (Fig. 11). 

Bataillard et al. (1993) described the integration of a series of thermocouples (thermopiles) on a silicon chip in order to increase the voltage output. The chip consists of an array of p-type silicon/aluminium thermocouples, connected in series and integrated in a n-type silicon epoxy layer grown on the silicon wafer. The overall size of the chip is only 5x5 mm. Several enzymes are immobilized on the array, and the chips are inserted into a FIA system. Glucose is monitored with coimmobilized glucose oxidase and catalase ranging from 2 to 100 mmol/1, urea (1-1000 mmol/1) with immobilized urease and penicillin (1-1000 mmol/1) with immobilized //-lactamase. 

This system is used to remove sugar present in low concentration in egg whites. The system may also be used to remove small amounts of oxygen from the head space of sealed containers by adding a packet containing glucose, oxidase, and catalase. 

Internal diffusional resistance is widely appreciated now, and tests for freedom from such Internal disguises are commonly used in kinetic studies. The level of complexity of diffusional intrusions is illustrated with consideration of an immobilized dual system glucose oxidase (E ) and catalase (E.) are used to oxidize glucose (G) to oxidized glucose (G ), and to de... 

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