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Enzyme immobilization

Dong-Mei Liu, Juan Chen, Yan-Ping Shi
In the present study, the chitosan-enriched magnetic composites (MCCs) were prepared by a novel and simple embedding method for the immobilization of α-glucosidase (α-Glu). The immobilized α-Glu could be easily separated from the reaction mixture under an external magnetic field owing to the magnetic support. With the MCCs-immobilized α-Glu, enzyme activity and stability were studied, and enzyme inhibitors were screened from traditional Chinese medicines (TCMs) and vegetables combined with capillary electrophoresis (CE)...
July 16, 2017: International Journal of Biological Macromolecules
Limin Guo, Zhao Li, Kyle Marcus, Steven Navarro, Kun Liang, Le Zhou, Prabhu Doss Mani, Stephen J Florczyk, Kevin R Coffey, Nina Orlovskaya, Yong-Ho Sohn, Yang Yang
Periodically patterned Au nanorods in TiO2 nanocavities (Au NRs@TiO2) were fabricated via magnetron sputtering followed by a thermal dewetting process. This innovative Au NRs@TiO2 heterostructure was used as a plasmonic sensing platform for photoelectrochemical detection of glucose and lactose. This Au NRs@TiO2 patterned heterostructure possesses superior sensing properties to other Au nanoparticle-based sensors because (i) localized surface plasmon resonance (LSPR) generated at Au/TiO2 interfaces enhanced sensitivity of glucose (lactose) amperometric detection; (ii) periodic Au nanocrystals in TiO2 nanocavities accelerated charge separation and transfer rate, especially under monochromatic blue light irradiation; (iii) discrete planar architectures comprising Au NRs immobilized on TiO2 substrates significantly improved stability and reusability of the sensors...
May 26, 2017: ACS Sensors
Christian Hoffmann, Manuel Pinelo, John M Woodley, Anders E Daugaard
Efficient immobilization of enzymes on support surfaces requires an exact match between the surface chemistry and the specific enzyme. A successful match would normally be identified through time consuming screening of conventional resins in multiple experiments testing individual immobilization strategies. In this study we present a versatile strategy that largely expands the number of possible surface functionalities for enzyme immobilization in a single, generic platform. The combination of many individual surface chemistries and thus immobilization methods in one modular system permits faster and more efficient screening, which we believe will result in a higher chance of discovery of optimal surface/enzyme interactions...
July 19, 2017: Biotechnology Progress
Kaycie Deyle, Xu-Dong Kong, Christian Heinis
Cyclic peptides can bind to protein targets with high affinities and selectivities, which makes them an attractive modality for the development of research reagents and therapeutics. Additional properties, including low inherent toxicity, efficient chemical synthesis, and facile modification with labels or immobilization reagents, increase their attractiveness. Cyclic peptide ligands against a wide range of protein targets have been isolated from natural sources such as bacteria, fungi, plants, and animals...
July 18, 2017: Accounts of Chemical Research
Yao Lu, Jing Zhu, Junling Shi, Yanlin Liu, Dongyan Shao, Chunmei Jiang
Higher alcohols are the byproducts of yeasts in alcohol fermentation and are harmful to human health at high concentrations. In this study, immobilized crude enzymes extracted from Geotrichum spp. strains S12 and S13 were separately employed to treat red wine, then GC and GC-MS analyses were used to determine the profiles of volatile compounds in untreated and treated wine samples. Immobilized enzymes from S13 (SA-S13E) were more active in decreasing higher alcohols than enzymes from S12. Conditions for preparing SA-S13E were optimized, and best results were obtained at a sodium alginate concentration of 35 g/L, calcium chloride of 20 g/L, and crude enzyme dosage of 3 mL...
July 17, 2017: Applied Microbiology and Biotechnology
Fernanda de Costa, Carla J S Barber, Yeon-Bok Kim, Darwin W Reed, Haixia Zhang, Arthur G Fett-Neto, Patrick S Covello
Triterpene saponins include bioactive compounds with structures consisting of triterpene aglycones (sapogenins) and one or more sugar moieties linked through acetal or ester glycosidic linkages at one or more sites. Centella asiatica (L.) Urban is a medicinal plant that contains bioactive ursane-type saponins, such as madecassoside and asiaticoside. In this work, glucosylation of triterpenoids in C. asiatica was investigated starting with plant extracts. An enzyme capable of glucosylating asiatic and madecassic acids was partially purified...
September 2017: Plant Science: An International Journal of Experimental Plant Biology
Xiaolong Han, Guodong Liu, Wenxia Song, Yinbo Qu
The production of sodium gluconate by enzymatic catalysis of delignified corn cob residue (DCCR) hydrolysate was studied. Penicillium oxalicum I1-13 was used for the production of cellulase with high β-glucosidase activity. A fed-batch saccharification process was developed to obtain high yields of glucose. At the end of hydrolysis, the concentration of glucose reached 145.80g/L. Glucose oxidase and catalase were co-immobilized to catalyze DCCR hydrolysate to produce sodium gluconate. Under the optimum conditions, 166...
June 23, 2017: Bioresource Technology
Xiaohui Lv, Boming Huang, Xiaoshan Zhu, Yuelu Jiang, Baiyang Chen, Yi Tao, Jin Zhou, Zhonghua Cai
The toxicity of fullerene (C60) to Daphnia magna has been a subject with increasing concerns. Nevertheless, the underlying mechanisms are still poorly understood. In the present study, we evaluated various aspects of the toxicological impacts of C60 on daphnia. After a 72-h exposure, the 50% effective concentration of C60 was 14.9 mg/L for immobilization, and 16.3 mg/L for mortality. Daphnia exhibited a quick uptake of C60 with a body burden value of 413 μg/g in wet weight in the 1 mg/L C60 treatment group...
July 14, 2017: Water Research
Muhammad Bilal, Tahir Rasheed, Hafiz M N Iqbal, Hongbo Hu, Wei Wang, Xuehong Zhang
Herein, we report the immobilization of in-house isolated horseradish peroxidase (HRP) from Armoracia rusticana with novel characteristics. The HRP was immobilized onto the self-fabricated polyvinyl alcohol-alginate (PVA-alginate) beads using sodium nitrate as a cross-linker. The PVA-alginate beads (2.0mm size) developed using 10% PVA and 1.5% sodium alginate showed maximal immobilization yield. The surface morphologies of the PVA-alginate (control) and immobilized-HRP were characterized by scanning electron microscopy (SEM)...
July 13, 2017: International Journal of Biological Macromolecules
Kh Pashangeh, M Akhond, H R Karbalaei-Heidari, G Absalan
Amino-functionalized magnetic nanoparticles (Fe3O4) have been investigated as a support for covalent immobilization of lipase. The nanoparticles were prepared by chemical coprecipitation method and subsequently were coated with 3-aminopropyltriethoxysilane (APTES) via silanization reaction. With glutaraldehyde, as the coupling agent, the lipase from Rhizopus oryzae was successfully immobilized onto the amino-functionalized magnetic nanoparticles. The synthesized support was characterized by transmission electron microscopy and Fourier transform infrared spectroscopy...
July 12, 2017: International Journal of Biological Macromolecules
Elin Moe, Filipe Rollo, Célia M Silveira, Murat Sezer, Peter Hildebrandt, Smilja Todorovic
Endonuclease III is a Fe-S containing bifunctional DNA glycosylase which is involved in the repair of oxidation damaged DNA. Here we employ surface enhanced IR spectroelectrochemistry and electrochemistry to study the enzyme from the highly radiation- and desiccation-resistant bacterium Deinococcus radiodurans (DrEndoIII2). The experiments are designed to shed more light onto specific parameters that are currently proposed to govern damage search and recognition by endonucleases III. We demonstrate that electrostatic interactions required for the redox activation of DrEndoIII2 may result in high electric fields that alter its structural and thermodynamic properties...
July 5, 2017: Spectrochimica Acta. Part A, Molecular and Biomolecular Spectroscopy
Mahmood H Akhtar, Khalil K Hussain, N G Gurudatt, Yoon-Bo Shim
A microfluidic structured-dual electrodes sensor comprising of a pair of screen printed carbon electrodes was fabricated to detect acetylcholine, where one of them was used for an enzyme reaction and another for a detection electrode. The former was coated with gold nanoparticles and the latter with a porous gold layer, followed by electropolymerization of 2, 2:5,2-terthiophene-3-(p-benzoic acid) (pTTBA) on both the electrodes. Then, acetylcholinesterase was covalently attached onto the reaction electrode, and hydrazine and choline oxidase were co-immobilized on the detection electrode...
July 5, 2017: Biosensors & Bioelectronics
Mihiri Seneviratne, Nishanta Rajakaruna, Muhammad Rizwan, H M S P Madawala, Yong Sik Ok, Meththika Vithanage
Heavy metal contamination in soils can influence plants and animals, often leading to toxicosis. Heavy metals can impact various biochemical processes in plants, including enzyme and antioxidant production, protein mobilization and photosynthesis. Hydrolyzing enzymes play a major role in seed germination. Enzymes such as acid phosphatases, proteases and α-amylases are known to facilitate both seed germination and seedling growth via mobilizing nutrients in the endosperm. In the presence of heavy metals, starch is immobilized and nutrient sources become limited...
July 12, 2017: Environmental Geochemistry and Health
Sriram Satagopan, Yuan Sun, Jon R Parquette, F Robert Tabita
BACKGROUND: With increasing concerns over global warming and depletion of fossil-fuel reserves, it is attractive to develop innovative strategies to assimilate CO2, a greenhouse gas, into usable organic carbon. Cell-free systems can be designed to operate as catalytic platforms with enzymes that offer exceptional selectivity and efficiency, without the need to support ancillary reactions of metabolic pathways operating in intact cells. Such systems are yet to be exploited for applications involving CO2 utilization and subsequent conversion to valuable products, including biofuels...
2017: Biotechnology for Biofuels
Patrick T O'Kane, Milan Mrksich
This paper describes an assay that can profile the binding of a protein to ligands, and can rank the affinities of a library of ligands. The method is based on the enhanced rate of an enzyme-mediated reaction that follows from colocalization of the enzyme and substrate by a protein-ligand interaction. This assay uses a self-assembled monolayer that presents a candidate peptide ligand for a receptor and a peptide substrate for an enzyme. The receptor is prepared as a fusion to the relevant enzyme so that binding of the receptor the immobilized ligand brings the enzyme to the surface where it can more rapidly modify its substrate...
July 9, 2017: Journal of the American Chemical Society
Celina M Miyazaki, Rohit Mishra, David J Kinahan, Marystela Ferreira, Jens Ducrée
Antibody immobilization on polymeric substrates is a key manufacturing step for microfluidic devices that implement sample-to-answer automation of immunoassays. In this work, a simple and versatile method to bio-functionalize poly(methylmethacrylate) (PMMA), a common material of such "Lab-on-a-Chip" systems, is proposed; using the Layer-by-Layer (LbL) technique, we assemble nanostructured thin films of poly(ethylene imine) (PEI) and graphene oxide (GO). The wettability of PMMA surfaces was significantly augmented by the surface treatment with (PEI/GO)5 film, with an 81% reduction of the contact angle, while the surface roughness increased by 600%, thus clearly enhancing wettability and antibody binding capacity...
June 27, 2017: Colloids and Surfaces. B, Biointerfaces
James F Ross, Angela Bridges, Jordan M Fletcher, Deborah Shoemark, Dominic Alibhai, Harriet E V Bray, Joseph L Beesley, William M Dawson, Lorna R Hodgson, Judith Mantell, Paul Verkade, Colin M Edge, Richard B Sessions, David Tew, Derek N Woolfson
An ability to organize and encapsulate multiple active proteins into defined objects and spaces at the nanoscale has potential applications in biotechnology, nanotechnology, and synthetic biology. Previously, we have described the design, assembly, and characterization of peptide-based self-assembled cages (SAGEs). These ≈100 nm particles comprise thousands of copies of de novo designed peptide-based hubs that array into a hexagonal network and close to give caged structures. Here, we show that, when fused to the designed peptides, various natural proteins can be co-assembled into SAGE particles...
July 11, 2017: ACS Nano
Urszula Klekotka, Magdalena Rogowska, Dariusz Satuła, Beata Kalska-Szostko
Ferrite nanoparticles with nominal composition Me0.5Fe2.5O4 (Me = Co, Fe, Ni or Mn) have been successfully prepared by the wet chemical method. The obtained particles have a mean diameter of 11-16 ± 2 nm and were modified to improve their magnetic properties and chemical activity. The surface of the pristine nanoparticles was functionalized afterwards with -COOH and -NH2 groups to obtain a bioactive layer. To achieve our goal, two different modification approaches were realized. In the first one, glutaraldehyde was attached to the nanoparticles as a linker...
2017: Beilstein Journal of Nanotechnology
D Ratautas, L Tetianec, L Marcinkevičienė, R Meškys, J Kulys
In this paper we designed and investigated bioanode with alcohol dehydrogenase (ADH) catalysing oxidation of glycerol and glyceraldehyde. The most effective bioanode was fabricated when ADH was immobilized on gold nanoparticles (AuNPs) modified with 4-aminothiophenol. This electrode catalysed the oxidation of both glycerol and glyceraldehyde thus demonstrating a consecutive two-step process. The bioanode generated the current density of 510µAcm(-2) at pH 7.0 and 0V vs. SCE. It was demonstrated that the electrode acted effectively due to the direct electron exchange between heme of ADH and modified AuNPs...
June 27, 2017: Biosensors & Bioelectronics
Jianhao Wang, Jie Fan, Li Liu, Shumin Ding, Xiaoqian Liu, Jianpeng Wang, Liqian Gao, Souvik Chattopadhaya, Peng Miao, Jiang Xia, Lin Qiu, Pengju Jiang
Herein, a novel assay has been developed for monitoring PreScission protease (His-PSP) mediated enzyme cleavage of ATTO 590 labeled peptide substrate (ATTO-LEV). This novel method is based on combining the use of capillary electrophoresis and fluorescence detection (CE-FL) to dynamically monitor the enzyme cleavage activity. A multivalent peptide substrate was first constructed by immobilizing His-tagged ATTO 590 labeled peptide substrate (ATTO-LEVH6) onto the surface of CdSe/ZnS quantum dots (QDs). Once successfully immobilized, the novel multivalent peptide substrate resulted in the Förster resonance energy transfer (FRET) from QDs to ATTO 590...
July 6, 2017: Electrophoresis
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