Deactivation studies of immobilized glucose oxidase

Krishnaswamy, Srinivas; Kittrell, J. R.

doi:10.1002/bit.260200605

Cited by 42 publications

(17 citation statements)

References 5 publications

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“…The half life of the catalyst is particularly important to address; this problem could be due to factors such as enzyme deactivation by H 2 O 2 or milk solids precipitation on the catalyst surface. Krishnaswamy and Kittrell (1978) reported severe deactivation of immobilized glucose oxidase by H 2 O 2 following a firstorder reaction; their profile of deactivation is very similar to that presented in Figure 1. Even though SCN" in the milk sample used was sufficient to achieve good LPS antimicrobial activity, a higher concentration of SCN" can protect the immobilized enzymes.…”

Section: Catalyst Stabilitysupporting

confidence: 71%

Antimicrobial effect of the lactoperoxidase system in milk activated by immobilized enzymes

1995

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Immobilized lactase and glucose oxidase were used to produce H 2 O 2 to activate the lactoperoxidase system in milk. The enzymes were immobilized on nylon pellets. With a ratio of 35 g of catalyst/L of milk, a concentration of 0.75 mM was produced in 3 min. Raw milk treatment with the catalyst reduced coliforms by 79%; Staphylococcus aureus reduction was 68%, psychrotrophs 91%, and fungi 100%. Results were similar when milk was treated by addition of H 2 O 2 . Thiocyanate was not limiting because addition of NaSCN did not increase the effectiveness of the lactoperoxidase system.The stability of the catalyst was poor when successive treatments were applied to milk, having lost one half of the activity every eight determinations. Activation of the lactoperoxidase system by immobilized enzymes could be of interest if stability could be ensured.

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Section: Catalyst Stabilitysupporting

confidence: 71%

Antimicrobial effect of the lactoperoxidase system in milk activated by immobilized enzymes

1995

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“…Immobilized glucose oxidase is capable of enzymatic activity associated with its reaction with glucose [14]. However, hydrogen peroxide generated by the initiation reaction is also capable of reacting with glucose-oxidase and rendering it inactive [15–17]. Therefore, the efficiency of glucose oxidase encapsulation in addition to enzyme inactivation by hydrogen peroxide dictates the effective active enzyme concentration trapped within the dynamically forming coating.…”

Section: Resultsmentioning

confidence: 99%

Kinetics of interfacial radical polymerization initiated by a glucose-oxidase mediated redox system

Shenoy

Bowman

2012

Biomaterials

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The reaction and coating kinetics for the glucose oxidase initiated interfacial polymerization are elaborated. The interfacial film grows rapidly and linearly with time, producing time-dependent controllable conformal coating thicknesses of up to a millimeter in less than 4 minutes. Bulk polymerization was only observed when the immersing media was stirred to induce higher mass transport rates. The dramatically different film thicknesses observed between different concentrations of glucose in the hydrogel and iron in the bulk media are demonstrated to be a result of an initial rapid growth phase following which the film grows at the same rate nearly independent of either the glucose or iron concentration. The polymerization rate and hence the thickness growth rate in this initial phase saturate at glucose and iron concentrations above 0.8 M and 0.63 mM, respectively. At iron concentrations above 0.05 mM, the film thickness at the end of 3 hours of reaction monotonically decreased with increasing iron concentration from 5.7 mm to 4.2 mm. The glucose oxidase is trapped by the growing polymerization front and can be used as the sole enzymatic precursor to coat a second polymeric layer. However, the rate of film growth of the second layer is 14-fold lower than the rate of film growth when bulk enzyme is present during the second stage coating process.

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“…The other substrate of GOx, oxygen is replenished by fast diffusion from outside the system. We note that among its various effects, H 2 O 2 can inhibit the activity of glucose oxidase in the particles, with the rate constant k 2 , as defined in Equation :

true H + E \to_{}^{k_{2}} \dots

…”

Section: Reaction‐diffusion Modeling Of Drug Releasementioning

confidence: 99%

Glucose‐Triggered Insulin Release from Fe³⁺‐Cross‐linked Alginate Hydrogel: Experimental Study and Theoretical Modeling

et al. 2017

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We study the mechanisms involved in the release, triggered by the application of glucose, of insulin entrapped in Fe -cross-linked alginate hydrogel particles further stabilized with a polyelectrolyte. Platelet-shaped alginate particles are synthesized containing enzyme glucose oxidase conjugated with silica nanoparticles, which are also entrapped in the hydrogel. Glucose diffuses in from solution, and production of hydrogen peroxide is catalyzed by the enzyme within the hydrogel. We argue that, specifically for the Fe -cross-linked systems, the produced hydrogen peroxide is further converted to free radicals via a Fenton-type reaction catalyzed by the iron cations. The activity of free radicals, as well as the reduction of Fe by the enzyme, and other mechanisms contribute to the decrease in density of the hydrogel. As a result, while the particles remain intact, void sizes increase and release of insulin ensues and is followed experimentally. A theoretical description of the involved processes is proposed and utilized to fit the data. It is then used to study the long-time properties of the release process that offers a model for designing new drug-release systems.

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Deactivation studies of immobilized glucose oxidase

Cited by 42 publications

References 5 publications

Antimicrobial effect of the lactoperoxidase system in milk activated by immobilized enzymes

Antimicrobial effect of the lactoperoxidase system in milk activated by immobilized enzymes

Kinetics of interfacial radical polymerization initiated by a glucose-oxidase mediated redox system

Glucose‐Triggered Insulin Release from Fe³⁺‐Cross‐linked Alginate Hydrogel: Experimental Study and Theoretical Modeling

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Deactivation studies of immobilized glucose oxidase

Cited by 42 publications

References 5 publications

Antimicrobial effect of the lactoperoxidase system in milk activated by immobilized enzymes

Antimicrobial effect of the lactoperoxidase system in milk activated by immobilized enzymes

Kinetics of interfacial radical polymerization initiated by a glucose-oxidase mediated redox system

Glucose‐Triggered Insulin Release from Fe3+‐Cross‐linked Alginate Hydrogel: Experimental Study and Theoretical Modeling

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Glucose‐Triggered Insulin Release from Fe³⁺‐Cross‐linked Alginate Hydrogel: Experimental Study and Theoretical Modeling