Using the Glucose Oxidase/Peroxidase System in Enzyme Kinetics

Bateman, Robert C.; Evans, Joyce J.

doi:10.1021/ed072pa240

Cited by 78 publications

(71 citation statements)

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“…Glucose oxidase from Asperilligus niger (GOx) (Sigma-Aldrich) was purified [42] before use and stored at 0.5 mg/mL in a phosphate buffer solution (PBS) (pH = 5, 50 mM) at -80˚C in small aliquots (1.5 mL) and was defrosted and stored at 4˚C when required. The specific activity of the purified GOx was determined using an ABTS Assay [43] and measured to be was prepared and allowed to mutarotate for 24 hours at 4˚C before use [44]. Glassy Carbon Electrodes (GCE) with a diameter of 3 mm were used for all experiments.…”

Section: Reagents and Materialsmentioning

confidence: 99%

Aqueous dispersions of reduced graphene oxide and multi wall carbon nanotubes for enhanced glucose oxidase bioelectrode performance

Grosse

Champavert

Gambhir

et al. 2013

Carbon

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(2013). Aqueous dispersions of reduced graphene oxide and multi wall carbon nanotubes for enhanced glucose oxidase bioelectrode performance. Carbon, 61 (September), 467-475. Aqueous dispersions of reduced graphene oxide and multi wall carbon nanotubes for enhanced glucose oxidase bioelectrode performance AbstractAqueous dispersions of reduced graphene oxide (rGO) and multi walled carbon nanotubes (MWCNT) were fabricated through a modified chemical reduction method. The significant advantage of the method developed here is the omission of any stabilising compound or organic solvent to obtain stable rGO-MWCNT dispersions. Significantly biological entities, in this case the enzyme glucose oxidase (GOx), can be successfully incorporated into the dispersion. These dispersions were characterised using XPS, SEM, zeta potential and particle size measurements which showed that the dispersion stability is not sacrificed with the addition of GOx, and significantly, the electrical properties of the rGO and MWCNTs are maintained. In this study, rGO acts as an effective dispersing agent for MWCNTs and does not affect the solubility or electroactivity of the GOx. Bioelectrodes fabricated from these rGO-MWCNT-GOx dispersions were characterised electrochemically to test their feasibility in facilitating direct electron transfer (DET) from the redox centre of the enzyme to the electrode. The DET results showed that the specific catalytic current generated at an optimised rGO-MWCNT-GOx electrode was 72 uA/ug which is 144 times more efficient than other literature values for similar systems. The remarkable specific catalytic current can be attributed to the use of purified enzyme, the efficiency of charge transfer within the rGO-MWCNT composite and the ability of the electrode to facilitate direct electron transfer. Abstract:Aqueous dispersions of reduced Graphene Oxide (rGO) and multi walled carbon nanotubes (MWCNT) were fabricated through a modified chemical reduction method. The significant advantage of the method developed here is the omission of any stabilizing compound or organic solvent to obtain stable rGO-MWCNT dispersions. Significantly biological entities, in this case the enzyme glucose oxidase (GOx), can be successfully incorporated into the dispersion. These dispersions were characterised using XPS, SEM, zeta potential and particle size measurements which showed that the dispersion stability is not sacrificed with the addition of GOx, and significantly, the electrical properties of the rGO and MWCNTs are maintained. In this study, rGO acts as an effective dispersing agent for MWCNTs and does not affect the solubility or electroactivity of the GOx.Bioelectrodes fabricated from these rGO-MWCNT-GOx dispersions were characterised electrochemically to test their feasibility in facilitating direct electron transfer (DET) from the redox centre of the enzyme to the electrode. The DET results showed that the specific catalytic current generated at an optimized rGO-MWCNT-GOx electrode was 72 µA/µg GOx, which is 144 times m...

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Section: Reagents and Materialsmentioning

confidence: 99%

Aqueous dispersions of reduced graphene oxide and multi wall carbon nanotubes for enhanced glucose oxidase bioelectrode performance

Grosse

Champavert

Gambhir

et al. 2013

Carbon

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“…Glucose concentrations were determined using an enzymatic assay based on glucose oxidase (from Aspergillus niger; Sigma-Aldrich, Buchs, Switzerland) and horseradish peroxidase (Sigma-Aldrich, Buchs, Switzerland) utilizing 2,2=-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) (Sigma-Aldrich, Buchs, Switzer- land) as a chromogenic substrate (19,20). In short, 20 l of sample was mixed with 80 l sodium phosphate buffer (0.1 mol liter Ϫ1 , pH 7), and subsequently, 40 l glucose oxidase solution (100 U ml buffer Ϫ1 ) was added.…”

Section: Methodsmentioning

confidence: 99%

A Defined, Glucose-Limited Mineral Medium for the Cultivation of Listeria spp

Schneebeli

Egli

2013

Appl Environ Microbiol

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Members of the genus Listeria are fastidious bacteria with respect to their nutritional requirements, and several minimal media described in the literature fail to support growth of all Listeria spp. Furthermore, strict limitation by a single nutrient, e.g., the carbon source, has not been demonstrated for any of the published minimal media. This is an important prerequisite for defined studies of growth and physiology, including "omics." Based on a theoretical analysis of previously published mineral media for Listeria, an improved, well-balanced growth medium was designed. It supports the growth, not only of all tested Listeria monocytogenes strains, but of all other Listeria species, with the exception of L. ivanovii. The growth performance of L. monocytogenes strain Scott A was tested in the newly designed medium; glucose served as the only carbon and energy source for growth, whereas neither the supplied amino acids nor the buffering and complexing components (MOPS [morpholinepropanesulfonic acid] and EDTA) supported growth. Omission of amino acids, trace elements, or vitamins, alone or in combination, resulted in considerably reduced biomass yields. Furthermore, we monitored the specific growth rates of various Listeria strains cultivated in the designed mineral medium and compared them to growth in complex medium (brain heart infusion broth [BHI]). The novel mineral medium was optimized for the commonly used strain L. monocytogenes Scott A to achieve optimum cell yields and maximum specific growth rates. This mineral medium is the first published synthetic medium for Listeria that has been shown to be strictly carbon (glucose) limited.

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“…IABETES mellitus is a deficiency in which the body cannot regulate the amount of glucose (sugar) in the blood [1]. The glucose present in the body provides the energy to perform person's daily activities.…”

Section: Introductionmentioning

confidence: 99%