Entrapment of glucose oxidase within gold converts it to a general monosaccharide-oxidase

Baruch-Shpigler, Yael; Avnir, David

doi:10.1038/s41598-021-90242-2

Cited by 5 publications

(6 citation statements)

References 52 publications

(52 reference statements)

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“…The slope of the absorbance fitted line (Fig. 5a) of free GOx (y = 0.003x + 0.225) and GOx-ALG-NCs (y = 0.003x + 0.340) was found to be similar, indicating that entrapped enzyme had similar catalytic activity as free GOx enzyme [43]. Figure 5b exhibited the effect of different pHs on the relative activity of enzymes in GOx-ALG-MCNPs.…”

Section: Protein Structure Ability/enzyme Activity Assaymentioning

confidence: 87%

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Oral Glucose-Responsive Nanocarrier System for Management of Diabetes

et al. 2022

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Background:The regulation of postprandial blood glucose concentration in a diabetic person is a toilsome task by the conventional approaches. The continuous monitoring and subcutaneous injection of insulin are always imperative for diabetes management. To overcome the hurdle associated with the conventional system, a glucose-responsive nanoparticle (NP)-based approach was developed for oral insulin administration. The objective of the work is the formulation and characterization of a nanocarrier-based bio-responsive, self-regulated oral insulin drug delivery system. Methods:The mannose ligand-conjugated NPs were prepared by the inotropic gelation method in which insulin and glucose oxidase enclosed alginate nanocarrier cross-linked by tripolyphosphate. The prepared NPs were filled into the enteric-coated capsule and their release profile was determined at different pH and glucose concentrations. NPs were characterized by size distribution, % drug entrapment, enzyme activity, and in vivo and in vitro drug release studies. Results:The average size, surface potential, % drug entrapment of optimized NPs were 245.52 ± 3.37 nm, 22.12 ± 2.13, and 76.15±1.3%, respectively. The release of insulin from optimized NPs (GOx-ALG-MCNPs) (98.56±0.06%) occurs only at higher sugar concentrations (≥ 400 mg/dL) and prevents the release at low sugar concentrations (< 100 mg/dL). The enteric capsule shell protected the formulation to the gastric environment upon oral administration and directed them into the intestine. Mucoadhesion characteristics of NPs prolonged intestinal retention to make them available for cellular uptake. Glucose sensitivity and glucose-dependent effect on different pH environments study revealed that NPs released the drug only at higher concentrations of sugar solution while inhibiting the release at normal and lower sugar concentrations. Besides, compared to other prepared formulations, the GOx-ALG-MCNPs displayed controlled insulin release in response to glucose concentration.Conclusions: An important finding of GOx-ALG-MCNPs is autoregulating, glucose-responsive behavior imparting a significantly controlled lowering of blood glucose in an animal model. The findings reveal that the developed glucose-responsive NPs may prove to be a potential strategy for oral insulin delivery.

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Section: Protein Structure Ability/enzyme Activity Assaymentioning

confidence: 87%

“…The yield of the prepared system: GOx-ALG-NCs, MCNPs, GOx-MCNPs, and GOx-ALG-MCNPs were 70. 43 The entrapment efficiency of insulin in the GOx-ALG-MC-NPs was low to MCNPs because of the entrapment of dual protein GOx-ALG-NCs and insulin. The entrapment of multiple components slightly increases the size.…”

Section: Entrapment Efficiencymentioning

confidence: 99%

Oral Glucose-Responsive Nanocarrier System for Management of Diabetes

et al. 2022

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“…In an earlier report 11 , we have shown that the entrapment of GOx within a 3D metallic matrix of gold, enables the extension of its activity to fructose, xylose and L-glucose, apparently due to conformational changes that open the channel leading to the two active sites of this dimeric protein. That preliminary observation pointed out to the possibility that the active site of GOx, if the right conditions are found to expose it by removing penetration restrictions, has the potential to operate any desired sugar molecule, including saccharides that lack a natural speci c oxidase.…”

Section: Introductionmentioning

confidence: 87%

“…Finally, 40 mg of zinc granules were added, and the reaction mixture was stirred overnight at room temperature. The rest of the procedure was exactly as mentioned above 11 .…”

Section: Methodsmentioning

confidence: 99%

Glucose oxidase converted into a general sugar-oxidase

Baruch-Shpigler

Avnir

2022

Preprint

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Entrapment of glucose oxidase (GOx) within metallic gold converts this widely used enzyme into a general saccharide oxidase. The following sugar molecules were oxidized by the entrapped enzyme (in addition to D-glucose): L-glucose, fructose, xylose,, glucose-6-phosphate, sucrose, lactose, methylglucoside, and the tri-saccharide raffinose. None of these sugars except raffinose has a natural specific oxidase. The origin of this generalization of activity is attributed to the strong protein-gold 3D interactions and to the strong interactions of co-entrapped cetyltrimethylammonium bromide (CTAB) with gold on one hand, and with the protein on the other hand. It is proposed that these interactions induce conformational changes in the channel leading to the active site, which is located at the interface between the two units of the dimeric GOx protein. The observations are compatible with affecting the specific conformation change of pulling apart and opening this gate-keeper, rendering the active site accessible to a variety of substrates. In addition to converting a common enzyme to an oxidase for common sugars which lack it, the entrapment methodology was found to be beneficial in increasing the thermal stability of GOx up to 100 oC and in allowing its convenient recyclability, two features of practical importance.

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“…The most studied GOx from Aspergillus niger (AnGOx) has been reported to have 270 times lower activity on d -xylose than on d -glucose. 8 Previously, the oxidation of d -xylose with AnGOx was achieved using an excessive amount of enzyme 9 or entrapping it with metallic gold, 10 which is costly for industrial processes. Many sugar dehydrogenases also have the capacity to oxidize d -xylose at the C1 position and have been used for the development of d -xylose biosensors or the production of d -xylonate.…”

Section: Introductionmentioning

confidence: 99%