Immobilization of enzymes through non-covalent binding to substituted agaroses

1973 ◽  
Vol 53 (4) ◽  
pp. 1137-1144 ◽  
Author(s):  
B.H.J. Hofstee
Keyword(s):  
Covalent Binding ◽  
Immobilization Of Enzymes

Protein Immobilization in Metal–Organic Frameworks by Covalent Binding

2014 ◽  
Vol 67 (11) ◽  
pp. 1629 ◽  
Author(s):  
Xuan Wang ◽  
Trevor A. Makal ◽  
Hong-Cai Zhou
Keyword(s):  
Enzymatic Activity ◽  
Enzyme Immobilization ◽  
Working Conditions ◽  
Active Site ◽  
Covalent Binding ◽  
Metal Organic Frameworks ◽  
Protein Immobilization ◽  
Immobilization Of Enzymes ◽  
Metal Organic ◽  
Biological Catalysis

Metal–organic frameworks (MOFs), possessing a well defined system of pores, demonstrate extensive potential serving as a platform in biological catalysis. Successful immobilization of enzymes in a MOF system retains the enzymatic activity, renders the active site more accessible to the substrate, and promises recyclability for reuse, and solvent adaptability in a broad range of working conditions. This highlight describes enzyme immobilization on MOFs via covalent binding and its significance.

scholarly journals Magnetic Nanomaterials as Biocatalyst Carriers for Biomass Processing: Immobilization Strategies, Reusability, and Applications

2021 ◽  
Vol 7 (10) ◽  
pp. 133
Author(s):  
Mayra A. Mariño ◽  
Stephanie Fulaz ◽  
Ljubica Tasic
Keyword(s):  
Polymer Brushes ◽  
Biomass Conversion ◽  
Covalent Binding ◽  
Sol Gel ◽  
Careful Analysis ◽  
Magnetic Nanomaterials ◽  
Magnetic Carriers ◽  
Biomass Processing ◽  
Immobilization Of Enzymes ◽  
Coated Surfaces

Environmental concerns, along with oil shortages, have increased industrial interest in biomass conversion to produce biofuels and other valuable chemicals. A green option in biomass processing is the use of enzymes, such as cellulases, hemicellulases, and ligninolytic (laccase and peroxidases), which have outstanding specificity toward their substrates and can be reused if immobilized onto magnetic nanocarriers. Numerous studies report the biocatalysts’ performance after covalent binding or adsorption on differently functionalized magnetic nanoparticles (MNPs). Functionalization strategies of MNPs include silica-based surfaces obtained through a sol–gel process, graphene oxide-based nanocomposites, polymer-coated surfaces, grafting polymer brushes, and others, which have been emphasized in this review of the immobilization and co-immobilization of enzymes used for biomass conversion. Careful analysis of the parameters affecting the performance of enzyme immobilization for new hybrid matrices has enabled us to achieve wider tolerance to thermal or chemical stress by these biosystems during saccharification. Additionally, it has enabled the application of immobilized laccase to remove toxic organic compounds from lignin, among other recent advances addressed here related to the use of reusable magnetic carriers for bioderived chemical manufacturing.

scholarly journals Immobilization of Enzymes by Polymeric Materials

Catalysts ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 1211
Author(s):  
Xingyi Lyu ◽  
Rebekah Gonzalez ◽  
Andalwisye Horton ◽  
Tao Li
Keyword(s):  
Immobilized Enzyme ◽  
Physical Adsorption ◽  
Covalent Binding ◽  
Polymeric Materials ◽  
Immobilized Enzymes ◽  
Operational Stability ◽  
Free Enzyme ◽  
External Stimulus ◽  
Harsh Environments ◽  
Immobilization Of Enzymes

Enzymes are the highly efficient biocatalyst in modern biotechnological industries. Due to the fragile property exposed to the external stimulus, the application of enzymes is highly limited. The immobilized enzyme by polymer has become a research hotspot to empower enzymes with more extraordinary properties and broader usage. Compared with free enzyme, polymer immobilized enzymes improve thermal and operational stability in harsh environments, such as extreme pH, temperature and concentration. Furthermore, good reusability is also highly expected. The first part of this study reviews the three primary immobilization methods: physical adsorption, covalent binding and entrapment, with their advantages and drawbacks. The second part of this paper includes some polymer applications and their derivatives in the immobilization of enzymes.

scholarly journals Use of Nanomaterials for the Immobilization of Industrially Important Enzymes

2021 ◽  
Author(s):  
Zarish Fatima
Keyword(s):  
Carbon Nanotubes ◽  
Covalent Binding ◽  
Stability Loss ◽  
Covalent Immobilization ◽  
Nano Materials ◽  
Multiwalled Carbon ◽  
Physiochemical Properties ◽  
Immobilization Of Enzymes ◽  
Conventional Methods ◽  
Limited Diffusion

Immobilization enables enzymes to be held in place so that they can be easily separated from the product when needed and can be used again. Conventional methods of immobilization include adsorption, encapsulation, entrapment, cross linking and covalent binding. However, conventional methods have several drawbacks including reduced stability, loss of biomolecules, less enzyme loading or activity and limited diffusion. The aim of this study is the evaluation of importance of nanomaterials for the immobilization of industrially important enzymes. Nano materials are now in trend for the immobilization of different enzymes due to their physiochemical properties. Gold nanoparticles, silver nanoparticles, nano diamonds, graphene, carbon nanotubes and others are used for immobilization. Among covalent and non-covalent immobilization of enzymes involving both single and multiwalled carbon nanotubes, non-covalent immobilization with functionalized carbon nanotubes is superior. Therefore, enzymes immobilized with nanomaterials possess greater stability, retention of catalytic activity and reusability of enzymes

scholarly journals Development of Chitosan Functionalized Magnetic Nanoparticles with Bioactive Compounds

Nanomaterials ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 1913
Author(s):  
Gordana Hojnik Podrepšek ◽  
Željko Knez ◽  
Maja Leitgeb
Keyword(s):  
Bioactive Compounds ◽  
Immobilized Enzyme ◽  
Cholesterol Oxidase ◽  
Covalent Binding ◽  
Enzyme Concentration ◽  
Synthesis Methods ◽  
Maghemite Nanoparticles ◽  
Mass Ratio ◽  
Functionalized Magnetic Nanoparticles ◽  
Immobilization Of Enzymes

In this study, magnetic maghemite nanoparticles, which belong to the group of metal oxides, were functionalized with chitosan, a non-toxic, hydrophilic, biocompatible, biodegradable biopolymer with anti-bacterial effects. This was done using different synthesis methods, and a comparison of the properties of the synthesized chitosan functionalized maghemite nanoparticles was conducted. Characterization was performed using scanning electron microscopy (SEM) and vibrating sample magnetometry (VSM). Characterizations of size distribution were performed using dynamic light scattering (DLS) measurements and laser granulometry. A chitosan functionalization layer was confirmed using potentiometric titration on variously synthesized chitosan functionalized maghemite nanoparticles, which is important for further immobilization of bioactive compounds. Furthermore, after activation of chitosan functionalized maghemite nanoparticles with glutaraldehyde (GA) or pentaethylenehexamine (PEHA), immobilization studies of enzyme cholesterol oxidase (ChOx) and horseradish peroxidase (HRP) were conducted. Factors influencing the immobilization of enzymes, such as type and concentration of activating reagent, mass ratio between carrier and enzyme, immobilization time and enzyme concentration, were investigated. Briefly, microparticles made using the chitosan suspension cross-linking process (MC2) proved to be the most suitable for obtaining the highest activity of immobilized enzyme, and nanoparticles functionalized with chitosan using the covalent binding method (MC3) could compete with MC2 for their applications.

Unlabeled Antibody Immunocytochemistry Applied to Murine Mammary Tumor Cells

1975 ◽  
Vol 33 ◽  
pp. 390-391
Author(s):  
Wm. J. Arnold ◽  
J. Russo ◽  
H. D. Soule ◽  
M. A. Rich
Keyword(s):  
Horseradish Peroxidase ◽  
Mammary Tumor ◽  
Covalent Binding ◽  
Petri Dish ◽  
Gamma Chain ◽  
Mammary Tumor Virus ◽  
Mammary Tumor Cells ◽  
Murine Mammary Tumor ◽  
Tumor Virus ◽  
Unlabeled Antibody

Our studies of mammary tumor virus have included the application of the unlabeled antibody enzyme method of Sternberger to mammary tumor derived mouse cells in culture and observation with an electron microscope. The method avoids the extravagance of covalent binding of indicator molecules (horseradish peroxidase) with precious antibody locator molecules by relying instead upon specific antibody-antigen linkages. Our reagents included: Primary Antibody, rabbit anti-murine mammary tumor virus (MuMTV) which was antiserum 113 AV-2; Secondary Antibody, goat anti-rabbit IgG gamma chain (Cappel Laboratories); andthe Indicator, rabbit anti-horseradish peroxidase - horseradish peroxidase complex (PAP) (Cappel Labs.). Dilutions and washes were made in 0.05 M Tris 0.15 M saline buffered to pH 7.4. Cell monolayers, after light fixation in glutaraldehyde, were incubated in place by a protocol adapted from Sternberger and Graham and Karnovsky, then embedded by our usual method for monolayers. Reagents were confined to specific areas by neoprene 0-rings (Parker Seal Co.) reducing the amount of reagent needed to 50 microliters, 1/6th of that required to wet a 35 mm petri dish.

Common modifications of selenocysteine in selenoproteins

2019 ◽  
Vol 64 (1) ◽  
pp. 45-53 ◽  
Author(s):  
Elias S.J. Arnér
Keyword(s):  
Amino Acids ◽  
Covalent Binding ◽  
Physicochemical Characteristics ◽  
Redox Active

Abstract Selenocysteine (Sec), the sulfur-to-selenium substituted variant of cysteine (Cys), is the defining entity of selenoproteins. These are naturally expressed in many diverse organisms and constitute a unique class of proteins. As a result of the physicochemical characteristics of selenium when compared with sulfur, Sec is typically more reactive than Cys while participating in similar reactions, and there are also some qualitative differences in the reactivities between the two amino acids. This minireview discusses the types of modifications of Sec in selenoproteins that have thus far been experimentally validated. These modifications include direct covalent binding through the Se atom of Sec to other chalcogen atoms (S, O and Se) as present in redox active molecular motifs, derivatization of Sec via the direct covalent binding to non-chalcogen elements (Ni, Mb, N, Au and C), and the loss of Se from Sec resulting in formation of dehydroalanine. To understand the nature of these Sec modifications is crucial for an understanding of selenoprotein reactivities in biological, physiological and pathophysiological contexts.

Small Molecule Permeation Across Membrane Channels: Chemical Modification to Quantify Transport Across OmpF

2018 ◽  
Author(s):  
Jiajun Wang ◽  
Jayesh Arun Bafna ◽  
Satya Prathyusha Bhamidimarri ◽  
Mathias Winterhalter
Keyword(s):  
Dwell Time ◽  
Covalent Binding ◽  
Channel Structure ◽  
Ion Current ◽  
E Coli ◽  
Current Fluctuation ◽  
Wide Range ◽  
Outer Membrane Channel ◽  
Biological Channels ◽  
Constriction Region

Biological channels facilitate the exchange of small molecules across membranes, but surprisingly there is a lack of general tools for the identification and quantification of transport (i.e., translocation and binding). Analyzing the ion current fluctuation of a typical channel with its constriction region in the middle does not allow a direct conclusion on successful transport. For this, we created an additional barrier acting as a molecular counter at the exit of the channel. To identify permeation, we mainly read the molecule residence time in the channel lumen as the indicator whether the molecule reached the exit of the channel. As an example, here we use the well-studied porin, OmpF, an outer membrane channel from <i>E. coli</i>. Inspection of the channel structure suggests that aspartic acid at position 181 is located below the constriction region (CR) and we subsequently mutated this residue to cysteine, where else cysteine free and functionalized it by covalent binding with 2-sulfonatoethyl methanethiosulfonate (MTSES) or the larger glutathione (GLT) blockers. Using the dwell time as the signal for transport, we found that both mono-arginine and tri-arginine permeation process is prolonged by 20% and 50% respectively through OmpF<sub>E181C</sub>MTSES, while the larger sized blocker modification OmpF<sub>E181C</sub>GLT drastically decreased the permeation of mono-arginine by 9-fold and even blocked the pathway of the tri-arginine. In case of the hepta-arginine as substrate, both chemical modifications led to an identical ‘blocked’ pattern observed by the dwell time of ion current fluctuation of the OmpF<sub>wt</sub>. As an instance for antibiotic permeation, we analyzed norfloxacin, a fluoroquinolone antimicrobial agent. The modulation of the interaction dwell time suggests possible successful permeation of norfloxacin across OmpF<sub>wt</sub>. This approach may discriminate blockages from translocation events for a wide range of substrates. A potential application could be screening for scaffolds to improve the permeability of antibiotics.

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