scholarly journals Chemical Modification of Glycoproteins’ Carbohydrate Moiety as a General Strategy for the Synthesis of Efficient Biocatalysts by Biomimetic Mineralization: The Case of Glucose Oxidase

Polymers ◽  
2021 ◽  
Vol 13 (22) ◽  
pp. 3875
Author(s):  
Marija D. Stanišić ◽  
Nikolina Popović Kokar ◽  
Predrag Ristić ◽  
Ana Marija Balaž ◽  
Milan Senćanski ◽  
...  
Keyword(s):  
Chemical Modification ◽  
Glucose Oxidase ◽  
Electrostatic Interactions ◽  
Specific Activity ◽  
Periodate Oxidation ◽  
Crystal Formation ◽  
General Strategy ◽  
Biomimetic Mineralization ◽  
Zeolitic Imidazolate Framework ◽  
Carbohydrate Components

Zeolitic imidazolate framework-8 (ZIF-8) is widely used as a protective coating to encapsulate proteins via biomimetic mineralization. The formation of nucleation centers and further biocomposite crystal growth is entirely governed by the pure electrostatic interactions between the protein’s surface and the positively charged Zn(II) metal ions. It was previously shown that enhancing these electrostatic interactions by a chemical modification of surface amino acid residues can lead to a rapid biocomposite crystal formation. However, a chemical modification of carbohydrate components by periodate oxidation for glycoproteins can serve as an alternative strategy. In the present study, an industrially important enzyme glucose oxidase (GOx) was selected as a model system. Periodate oxidation of GOx by 2.5 mM sodium periodate increased negative charge on the enzyme molecule, from −10.2 to −36.9 mV, as shown by zeta potential measurements and native PAGE electrophoresis. Biomineralization experiments with oxidized GOx resulted in higher specific activity, effectiveness factor, and higher thermostability of the ZIF-8 biocomposites. Periodate oxidation of carbohydrate components for glycoproteins can serve as a facile and general method for facilitating the biomimetic mineralization of other industrially relevant glycoproteins.

scholarly journals Decomposition of Glucose-Sensitive Layer-by-Layer Films Using Hemin, DNA, and Glucose Oxidase

Polymers ◽  
2020 ◽  
Vol 12 (2) ◽  
pp. 319 ◽  
Author(s):  
Kentaro Yoshida ◽  
Yu Kashimura ◽  
Toshio Kamijo ◽  
Tetsuya Ono ◽  
Takenori Dairaku ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Glucose Oxidase ◽  
Dna Cleavage ◽  
Electrostatic Interactions ◽  
Glucose Solution ◽  
Layer By Layer ◽  
Sensitive Layer ◽  
Physiological Conditions ◽  
Lbl Films ◽  
Low Glucose

Glucose-sensitive films were prepared through the layer-by-layer (LbL) deposition of hemin-modified poly(ethyleneimine) (H-PEI) solution and DNA solution (containing glucose oxidase (GOx)). H-PEI/DNA + GOx multilayer films were constructed using electrostatic interactions. The (H-PEI/DNA + GOx)5 film was then partially decomposed by hydrogen peroxide (H2O2). The mechanism for the decomposition of the LbL film was considered to involve more reactive oxygen species (ROS) that were formed by the reaction of hemin and H2O2, which then caused nonspecific DNA cleavage. In addition, GOx present in the LbL films reacts with glucose to generate hydrogen peroxide. Therefore, decomposition of the (H-PEI/DNA + GOx)5 film was observed when the thin film was immersed in a glucose solution. (H-PEI/DNA + GOx)5 films exposed to a glucose solution for periods of 24, 48 72, and 96 h indicated that the decomposition of the film increased with the time to 9.97%, 16.3%, 23.1%, and 30.5%, respectively. The rate of LbL film decomposition increased with the glucose concentration. At pH and ionic strengths close to physiological conditions, it was possible to slowly decompose the LbL film at low glucose concentrations of 1–10 mM.

Chemical modification of pullulan: 1. Periodate oxidation

Polymer ◽  
1993 ◽  
Vol 34 (12) ◽  
pp. 2628-2632 ◽  
Author(s):  
Dorine Bruneel ◽  
Etienne Schacht
Keyword(s):  
Chemical Modification ◽  
Periodate Oxidation

scholarly journals Used of Chemically Modified Titanium Dioxide Particles to Mediate the Non-isothermal Cold Crystallization of Poly(latic acid)

2020 ◽  
Vol 64 (2) ◽  
Author(s):  
J. A. Gonzalez-Calderon ◽  
Guadalupe Mendoza ◽  
M. G. Peña-Juárez ◽  
Elias Perez
Keyword(s):  
Titanium Dioxide ◽  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Chemical Modification ◽  
Dicarboxylic Acid ◽  
Crystallization Process ◽  
Polymer Chains ◽  
Cold Crystallization ◽  
Crystal Formation

In this work, the effect of the chemical modification of titanium dioxide particles on the non-isothermal crystallization process of polylactic acid (PLA) was studied. Cold crystallization in some polymers occurs above the glass transition temperature (Tg) when the polymer chains gain sufficient mobility to organize themselves into the ordered structure (i.e. the crystal structure) by folding the chains. Cold crystallization in general is caused by the ordering of the molecular chains in the crystalline PLA due to the increased mobility during heating. Through an analysis of the cool crystallization process in DSC at different cooling rates, it was observed that the behavior of PLA and its composites made with titanium dioxide, neat and functionalized with dicarboxylic acids, can be described through the models used for crystallization of the polymer carrying out during cooling, such as Mo’s and Jeziorny’s model. In addition, it was determined that the chemical modification of TiO2 performed with silane increases the crystallization rate in the last step of the process; while the chemical modification with dicarboxylic acid has an accelerated effect on the crystal formation process attributed to the affinity between the aliphatic part of this group and the polymer chains. Also, it was shown that the inclusion of the silanized particles has no effect on the energy requirement compared to the pure PLA process; however, the addition of particles with the dicarboxylic acid decreases the energy value required to complete the crystalline state due to affinity at the surface to immobilize the polymer chains. Finally, it is emphasized that the activation energy required to perform the crystallization of PLA and its composites has positive values, which is an indicator that the crystallization was performed while heating, after reaching and passing the glass transition temperature and before melting.

A tumor-cell biomimetic nanoplatform embedding biological enzymes for enhanced metabolic therapy

2021 ◽  
Author(s):  
Ping Ji ◽  
Tian-Yang Wang ◽  
Guo-Feng Luo ◽  
Wei-Hai Chen ◽  
Xian-Zheng Zhang
Keyword(s):  
Cell Membrane ◽  
Tumor Cell ◽  
Glucose Oxidase ◽  
Therapeutic System ◽  
Zeolitic Imidazolate Framework ◽  
Tumor Cell Membrane ◽  
Metabolic Therapy

A tumor cell membrane-camouflaged therapeutic system was fabricated to eliminate tumors by embedding the Apyrase and glucose oxidase (GOx) into zeolitic imidazolate framework-8 (ZIF-8) nanoparticles for tumor-targeted metabolic therapy. Experimental...

Glycopegylated Factor IX Enables Prolonged Efficacy After Subcutaneous Injection But Requires a Higher Than Expected Plasma Activity To Prevent Bleeding In Hemophilia B Mice

Blood ◽  
2013 ◽  
Vol 122 (21) ◽  
pp. 1104-1104
Author(s):  
Derek S Sim ◽  
Alan Brooks ◽  
Cornell Mallari ◽  
Yifan Xu ◽  
Rick I Feldman ◽  
...  
Keyword(s):  
Half Life ◽  
Subcutaneous Injection ◽  
Specific Activity ◽  
Periodate Oxidation ◽  
Factor Ix ◽  
Hemophilia B ◽  
Current Therapy ◽  
B Mice ◽  
Trough Levels ◽  
Plasma Activity

Abstract Background Reduced frequency of administration as well as subcutaneous (s.c.) injection would improve the treatment of Hemophilia B. Conjugation to polyethylene glycol (PEG) has been shown to increase the half-life of i.v. dosed Factor IX (FIX), but s.c. dosing of PEGylated FIX was not previously evaluated. Because s.c. dosing is limited by volume and bioavailability, we evaluated the combination of PEGylation with the increased specific activity variant R338A to reduce the amount of protein needed to provide therapeutic levels of FIX. Methods FIX-R338A was PEGylated on N-linked glycans in the activation peptide by periodate oxidation of sialic acid residues followed by conjugation to amino-oxy functionalized PEG. Pharmacokinetic (PK) profiles were determined in hemophilia B mice and cynomologous monkeys. Allometric scaling was used to predict dose regimens in humans. Prophylactic efficacy was determined in a Hemophilia B mouse tail bleeding model. Results 60kDaPEG-R338A had prolonged terminal half-life in mice (3-fold) and monkeys (5-fold) and the s.c. bioavailability was 44% and 35%, respectively. The volume of distribution was reduced 5-fold. To achieve a trough level of 3% FIX activity, s.c. dosing at weekly, bi-monthly and monthly intervals was predicted to require doses of 7, 25 and 220 IU/kg in patients. However, in a tail vein transection injury model, approximately 10-fold higher plasma FIX activity levels of PEGylated proteins were found to be needed to protect hemophilia B mice against bleeding than was required for i.v. dosed un-PEGylated recombinant FIX. This difference was observed for PEGylated wild-type and R338A proteins, dosed i.v or s.c. We hypothesize that this is related to the reduced distribution of PEGylated FIX to the extravascular compartment. Trough levels of 30% FIX activity were predicted to be achievable in humans after weekly and bi-monthly s.c. dosing at 70 and 260 IU/kg. Conclusions The PEGylation of FIX led to a significant improvement in both i.v. and s.c. PK. Unexpectedly, a 10-fold higher plasma activity was needed for PEGylated FIX to provide protection against bleeding in Hemophilia B mice, suggesting that trough levels of 10 to 30% of PEGylated FIX activity may be needed in patients to provide efficacy equivalent to current therapy of recombinant or plasma derived FIX. Nevertheless, 60kDaPEG-R338A has the potential to treat hemophilia B patients with once weekly or twice monthly subcutaneous injection. Disclosures: Sim: Bayer HealthCare: Employment. Brooks:Bayer HealthCare: Employment. Mallari:Bayer HealthCare: Employment. Xu:Bayer HealthCare: Employment. Feldman:Bayer HealthCare: Employment. Schneider:Bayer HealthCare: Employment. Patel:Bayer HealthCare: Employment. Blasko:Bayer HealthCare: Employment. Ho:Bayer HealthCare: Employment. Su:Bayer HealthCare: Employment. Liu:Bayer HealthCare: Employment. Laux:Bayer HealthCare: Employment. Murphy:Bayer HealthCare: Employment.

scholarly journals Development of antimicrobial packaging materials with immobilized glucose oxidase and lysozyme

2013 ◽  
Vol 11 (7) ◽  
pp. 1066-1078 ◽  
Author(s):  
Kristýna Hanušová ◽  
Lukáš Vápenka ◽  
Jaroslav Dobiáš ◽  
Linda Mišková
Keyword(s):  
Glucose Oxidase ◽  
Specific Activity ◽  
Immobilized Enzymes ◽  
Lactobacillus Helveticus ◽  
Listeria Ivanovii ◽  
Agar Media ◽  
Ft Ir ◽  
Immobilized Glucose Oxidase ◽  
And Storage ◽  
Ft Ir Spectroscopy

AbstractPackaging based on immobilization of antimicrobial enzymes provides a promising form of active packaging systems applicable in food processing. Glucose oxidase and lysozyme were immobilized by the Ugi reaction with cyclohexyl isocyanide and glutaraldehyde on polyamide and ionomer films partially hydrolysed by hydrochloric acid. The immobilization of the enzymes on the surface of films was confirmed by FT-IR spectroscopy and the films were characterized by the specific activity of the immobilized enzymes. The enzyme migration into model solutions and the effect of pH, temperature and storage time on the activity of immobilized enzyme were also evaluated. Immobilization of lysozyme onto polyamide and ionomer films resulted in the loss of enzyme activity. The polyamide and ionomer films with immobilized glucose oxidase inhibited the growth of bacteria Escherichia coli CNCTC 6859, Pseudomonas fluorescens CNCTC 5793, Lactobacillus helveticus CH-1, Listeria ivanovii CCM 5884 and Listeria innocua CCM 4030 on agar media.

SOLUBLE CARBON NANOTUBES: FUNDAMENTALS AND APPLICATIONS

2005 ◽  
Vol 04 (01) ◽  
pp. 119-137 ◽  
Author(s):  
NAOTOSHI NAKASHIMA
Keyword(s):  
Carbon Nanotubes ◽  
Chemical Modification ◽  
Physical Adsorption ◽  
Review Article ◽  
Crystal Formation ◽  
Mechanical And Thermal Properties ◽  
Organic Systems ◽  
High Potentials ◽  
Selective Chemical ◽  
Aqueous Micelles

Carbon nanotubes (CNTs) have been in the forefront of nanoscience and nanotechnology because of their remarkable electronic, mechanical, and thermal properties and specific functions. CNTs have high potentials for possible applications in the fields of energy, electronics, IT, and materials. However, because of the insolubility of the nanotubes in solvents, chemical, biochemical, and biological (medical) approaches using these materials have been rather limited. Soluble CNTs in aqueous and organic systems are of interests since they may open the door in such fields. In this review article, (i) the dissolution of CNTs in water and in organic solvents by using chemical modification and physical adsorption and their applications to chemical and biological areas, (ii) separation of metallic SWNTs and semiconducting SWNTs by the combination of individual dissolution of SWNTs and the selective chemical modification, (iii) the preparation of nanotube films and fibers from dissolved/dispersed SWNTs in aqueous micelles, and (iv) CNT liquid crystal formation are summarized.

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