Optimal Study of Co-Immobilized GOD/CAT on Cross-Linked Chitosan Microsphere Containing L-Lysine

2011 ◽  
Vol 236-238 ◽  
pp. 926-929 ◽  
Author(s):  
Xiao Hua Zhou ◽  
Ying Li Wang ◽  
Xia Li Su
Keyword(s):  
Enzyme Activity ◽  
Glucose Oxidase ◽  
Half Life ◽  
Immobilized Enzyme ◽  
Activity Ratio ◽  
Cross Linking ◽  
Chitosan Microsphere ◽  
Activity Recovery ◽  
The Cross ◽  
Optimized Conditions

Glucose oxidase (GOD) and catalase (CAT) were co-immobilized on the cross-linked chitosan microsphere containing L-Lysine (CCL) by the method of absorption-crosslink, with cross-linking agent of glutaraldehyde. The optimized conditions of the co-immobilization are as follows: activity ratio of GOD and CAT is 0.78:1, concentration of glutaraldehyde is 0.17mmol/L, and the immobilizing process last for 3 hours. The enzyme activity of co-immobilized enzyme is 15.3U/mg and activity recovery is 50.1%. The half life is 231 days, 2.4 times of immobilized GOD.

Preparation and Properties of Cross-Linked Enzyme Aggregates of Cellulase

2012 ◽  
Vol 581-582 ◽  
pp. 257-260 ◽  
Author(s):  
Bing Li ◽  
Shou Li Dong ◽  
Xiao Ling Xie ◽  
Zhen Bo Xu ◽  
Lin Li
Keyword(s):  
Enzyme Activity ◽  
Cross Linking ◽  
Optimal Temperature ◽  
Carrier Free ◽  
The Cross

A new carrier-free cross-linked aggregates of cellulase (CLEAs-C) via precipitation with ammonia sulfate and cross-linking with glutaraldehyde was prepared. Efficient enzyme activity was obtained when cellulase and glutaraldehyde concentration was 50mg/mL and 3% (v/v) respectively. The cross-linking time and temperature were also important parameters for immobilization. Optimal temperature and pH of the CLEA–C were evaluated. The CLEAs-C displayed good stabilities, after stored at 4○C for 28 days storage, the CLEAs retained more than 80% initial activities.

Ionic Liquid-Regenerated Cellulose Beads as Solid Support Matrices for Papain Immobilization

2012 ◽  
Vol 535-537 ◽  
pp. 2349-2352
Author(s):  
Song Kun Yao ◽  
Qiu Jin Li ◽  
Wei Zhang ◽  
Ji Xian Gong ◽  
Jian Fei Zhang
Keyword(s):  
Ionic Liquid ◽  
Enzyme Activity ◽  
Room Temperature ◽  
Immobilized Enzyme ◽  
Solid Support ◽  
Cross Linking ◽  
Regenerated Cellulose ◽  
Ester Hydrochloride ◽  
Imidazolium Chloride ◽  
Scanning Electron

A beads based on cellulose and the room temperature ionic liquid 1-butyl-3-methyl imidazolium chloride ([Bmim]Cl) was prepared. Regenerated cellulose beads were modified with silane, and characterized by scanning electron microscopy. Papain was immobilized on the beads used two different methods including glutaraldehyde and covalent cross-linking method. The immobilized enzyme activity of bead was determinated by BAEE (N-benzoyl- DL-arginine ethyl ester hydrochloride) determination. According to the enzyme activity and immobilization rate compared with covalent cross-linking method, glutaraldehyde cross-linking method is more suitable for amino-modified.

Co-Immobilization of Glucose Oxidase-Catalase: Optimization of Immobilization Parameters to Improve the Immobilization Yield

2011 ◽  
Vol 7 (2) ◽  
Author(s):  
Sandip B Bankar ◽  
Mahesh V Bule ◽  
Rekha S Singhal ◽  
Laxmi A Ananthanarayan
Keyword(s):  
Glucose Oxidase ◽  
Response Surface ◽  
Glass Bead ◽  
Cross Linking ◽  
Optimization Strategy ◽  
Composite Optimization ◽  
The Cross ◽  
Glass Surfaces ◽  
Central Composite ◽  
Potential Use

Co-immobilization of glucose oxidase (EC 1.1.3.4) and catalase (EC 1. 11.1.6) on non-porus glass surfaces using ?-aminopropyltriethoxysilane and polyethyleneimine as an activator and gluteraldehyde as cross linking agent has been carried out for its potential use. Polyethyleneimine was found to be a superior immobilization activator than ?-aminopropyltriethoxysilane. In present study, the effects of rough and smooth beads and optimization of the ratio of enzyme concentrations, activator material and concentration of the cross linking agent were investigated using response surface technology. With optimized concentration of glucose oxidase to catalase ratio (0.97), polyethyleneimine (150 mg/l) and gluteraldehyde (15 ml), the effect of glass bead concentration for maximum immobilization yield was investigated. Central composite optimization strategy with 16 experiments increased immobilization yield from 82.63% to 92.74%. It was observed that 0.3 ml of beads per 120 U of glucose oxidase were necessary for higher immobilization yield.

scholarly journals A histochemical model dealing with an immobilized glucose oxidase-peroxidase system. The influence of diffusion limitations on histochemical results.

1980 ◽  
Vol 28 (9) ◽  
pp. 961-968 ◽  
Author(s):  
Y Malpiece ◽  
M Sharan ◽  
J N Barbotin ◽  
P Personne ◽  
D Thomas
Keyword(s):  
Glucose Oxidase ◽  
Immobilized Enzyme ◽  
Direct Method ◽  
Cross Linking ◽  
Kinetic Properties ◽  
Diffusion Limitations ◽  
Activity Measurements ◽  
Simulation Based ◽  
Insoluble Product ◽  
Immobilized Glucose Oxidase

A histochemical model dealing with an immobilized bienzyme system (glucose oxidase-peroxidase) is presented. The model is an artificial proteic membrane obtained by a previously described co-cross-linking process. The kinetic properties of free and immobilized horseradish peroxidase were studied when 3,3'-diaminobenzidine is used as a hydrogen donor substrate. A new direct method was developed for immobilized enzyme activity measurements. Computer simulation based on experimental kinetic parameters was performed in order to discuss electron microscopy results. By changing diffusion limitations, various profiles of insoluble product were visualized inside the proteic film and no geometrical similarity was seen between enzyme distributions and insoluble osmiophilic product patterns.

scholarly journals Chemical cross-linking of a dimeric protein on a modified lectin matrix. A general probe for the chemical topology of oligomeric glycoproteins

1981 ◽  
Vol 193 (3) ◽  
pp. 825-828 ◽  
Author(s):  
S Pillai
Keyword(s):  
Glucose Oxidase ◽  
Three Dimensional ◽  
Dimensional Structure ◽  
Cross Linking ◽  
Low Density ◽  
Amino Groups ◽  
Lysine Residues ◽  
The Cross ◽  
Interfacial Surfaces ◽  
Chemical Cross Linking

A dimeric glycoprotein, glucose oxidase, was allowed to react with lysine-specific cross-linkers, both when immobilized on a succinoylated lectin matrix at a critically low density and also at a high density in solution. Analysis of the cross-linked complexes thus obtained led to the following inferences with regard to the structure of this protein. (1) Of the 15 lysine residues on each glucose oxidase protomer, none is available on the non-interfacial surfaces. (2) Assuming that this protein possesses C2 symmetry with isologous bonding between subunits, it may be inferred that on each promoter there are at least two lysine clusters along or close to the interprotomeric interface. (3) These ‘interfacial’ lysine residues on each protomer are so oriented that the epsilon-amino groups of lysine residues a and b on protomer 1 ‘face’, and are very close to, the epsilon-amino groups of lysine residues b' and a' respectively on protomer 2. General inferences on the geometry of dimeric proteins derivable from an analysis of the cross-linked complexes obtained (as well as those not seen) by using this low-density matrix cross-linking approach were enumerated. Modified lectin matrices may prove useful in studying the three-dimensional structure of glycoproteins, particularly non-crystallizable oligomers.

Development and Characterization of LBG-PVA Interpenetrating Networks Incorporating Gliclazide for Sustained Release

2020 ◽  
Vol 15 ◽  
Author(s):  
Ashish Katoch ◽  
Manju Nagpal ◽  
Malkiet Kaur ◽  
Manjinder Singh ◽  
Geeta Aggarwal ◽  
...  
Keyword(s):  
Solid State ◽  
Sustained Release ◽  
Half Life ◽  
Solid State Nmr ◽  
Oral Dosage ◽  
Cross Linking ◽  
Interpenetrating Networks ◽  
Dsc Studies ◽  
Biological Half Life ◽  
Percentage Yield

Background: Controlled oral dosage forms have always been preferred for drugs with variable absorption, and short biological half life and frequent dosing. The prime goal with sustained release systems is to maintain uniform therapeutic blood levels for longer periods of time. Interpenetrating networks (IPNs) have been evidenced as uniform sustained release systems. In current study, polyvinyl alcohol (PVA) and locust bean gum (LBG) based IPNs were developed for the oral sustained release drug delivery of gliclazide (shows variable absorption). Method: The IPNs were synthesized by emulsion cross-linking method using glutaraldehyde (GA) as a cross linking agent. Gliclazide is a potential second generation, short-acting sulfonylurea oral hypoglycemic agent is having a short biological half-life (2-4 h), variable absorption and poor oral bioavailability. Various batches of IPNs were formulated by varying LBG: PVA ratio and evaluated for percentage yield, drug entrapment efficiency (DEE), swelling properties and in vitro drug release studies. Further characterizations were done by Fourier Transform Infrared Spectroscopy (FTIR), C13 Solid state NMR, X-Ray diffraction study (XRD), Scanning electron microscopy (SEM), and Differential scanning microscopy (DSC) studies. Results: The percentage yield, drug entrapment and equilibrium swelling was observed to be dependent on PVA-LBG ratio and GA amount. Sustained release of drug was observed in all IPN formulations (approx 59 - 86% in 8 h in various batches) with variable release kinetics. SEM studies revealed the regular structures of IPNs. FTIR, XRD, C13 Solid state NMR and DSC studies proposed that drug was successfully incorporated into the formed IPNs. Conclusion: IPNs of LBG and PVA can be used as a promising carrier with uniform sustained release characteristics.

scholarly journals Investigation of the functional network modifier loading on the stoichiometric ratio of epoxy resins and their dielectric properties

2021 ◽  
Author(s):  
Istebreq A. Saeedi ◽  
Sunny Chaudhary ◽  
Thomas Andritsch ◽  
Alun S. Vaughan
Keyword(s):  
Glass Transition ◽  
Dielectric Properties ◽  
Electrical Properties ◽  
Epoxy Resins ◽  
Functional Network ◽  
Cross Linking ◽  
Network Modifier ◽  
Epoxy Resin System ◽  
The Cross ◽  
The Impact

AbstractReactive molecular additives have often been employed to tailor the mechanical properties of epoxy resins. In addition, several studies have reported improved electrical properties in such systems, where the network architecture and included function groups have been modified through the use of so-called functional network modifier (FNM) molecules. The study reported here set out to investigate the effect of a glycidyl polyhedral oligomeric silsesquioxane (GPOSS) FNM on the cross-linking reactions, glass transition, breakdown strength and dielectric properties of an amine-cured epoxy resin system. Since many previous studies have considered POSS to act as an inorganic filler, a key aim was to consider the impact of GPOSS addition on the stoichiometry of curing. Fourier transform infrared spectroscopy revealed significant changes in the cross-linking reactions that occur if appropriate stoichiometric compensation is not made for the additional epoxide groups present on the GPOSS. These changes, in concert with the direct effect of the GPOSS itself, influence the glass transition temperature, dielectric breakdown behaviour and dielectric response of the system. Specifically, the work shows that the inclusion of GPOSS can result in beneficial changes in electrical properties, but that these gains are easily lost if consequential changes in the matrix polymer are not appropriately counteracted. Nevertheless, if the system is appropriately optimized, materials with pronounced improvements in technologically important characteristics can be designed.

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