Read by QxMD icon Read

Enzyme immobilization

Libo Zhu, Dejian Gu, Quanjun Liu
There are many techniques for the detection of molecules. But detection of molecules through solid-state nanopore in a solution is one of the promising, high-throughput, and low-cost technology used these days. In the present investigation, a solid-state nanopore platform was fabricated for the detection of hydrogen peroxide (H2O2), which is not only a label free product but also a significant participant in the redox reaction. We have successfully fabricated silicon nitride (Si3N4) nanopores with diameters of ~50 nm by using a focused Ga ion beam, the inner surface of the nanopore has been modified with horseradish peroxidase (HRP) by employing carbodiimide coupling chemistry...
December 2017: Nanoscale Research Letters
Lixia Zhao, Dan Wang, Gen Shi, Ling Lin
The specificity for early diagnostic of prostate-specific antigen (PSA) is low because the current technology mostly allows the detection of only one biomarker at one time. In this work, a dual-labeled chemiluminescence enzyme immunoassay (CLEIA) for simultaneous measurement of total PSA (TPSA) and free PSA (FPSA) was proposed. Anti-PSA McAb (Mab1) was immobilized on a microplate as the solid phase, horseradish peroxidase (HRP)-labeled anti-TPSA monoclonal antibody (McAb2) and alkaline phosphatase (ALP)-labeled anti-FPSA McAb3 were used as detection antibodies...
June 21, 2017: Luminescence: the Journal of Biological and Chemical Luminescence
Vincent Morris Friebe, Diego Millo, David Swainsbury, Michael R Jones, Raoul N Frese
The high quantum efficiency of photosynthetic reaction centers make them attractive for bioelectronic and biophoto-voltaic applications. However, much of the native reaction center efficiency is lost in communication between surface bound reaction centers and electrode materials. State of the art biophotoelectrodes utilizing cytochrome c (cyt c) as a biological wiring agent have at best approached 32% retained RC quantum efficiency. However, bottlenecks in cyt c -mediated electron transfer have not been fully elucidated...
June 21, 2017: ACS Applied Materials & Interfaces
Ingrid Dayana Soto, Sindy Escobar, Monica Mesa
The interactions between Thermomyces lanuginosus lipase (TLL) and phenyl silica-based supports affect the immobilization mechanisms and their catalytic behavior. The modulation of phenyl groups density on the silica surface and porous characteristics were determined by TGA, FTIR, (29)Si NMR and N2 adsorption porosimetry. The correlation of the affinity constant and maximum adsorption capacity with the lixiviation results allowed determine differences in the enzyme adsorption mechanism in function of the immobilization pH and phenyl groups density...
October 1, 2017: Materials Science & Engineering. C, Materials for Biological Applications
Julie Ducharme, Karine Auclair
Bioconjugation, defined as chemical modification of biomolecules, is widely employed in biological and biophysical studies. It can expand functional diversity and enable applications ranging from biocatalysis, biosensing and even therapy. This review summarizes how chemical modifications of cytochrome P450 enzymes (P450s or CYPs) have contributed to improving our understanding of these enzymes. Genetic modifications of P450s have also proven very useful but are not covered in this review. Bioconjugation has served to gain structural information and investigate the mechanism of P450s via photoaffinity labeling, mechanism-based inhibition (MBI) and fluorescence studies...
June 15, 2017: Biochimica et Biophysica Acta
Dhanya Vishnu, Gerard Neeraj, Ramachandran Swaroopini, Ravi Shobana, Vaidyanathan Vinoth Kumar, Hubert Cabana
In this study, a tailor-made biocatalyst consisting of a co-immobilized lignolytic enzyme cascade on multi-functionalized magnetic silica microspheres (MSMS) was developed. Physical adsorption was the most promising strategy for the synthesis of individual immobilized laccase (IL), immobilized versatile peroxidase (IP), as well as co-immobilized laccase (Lac) and versatile peroxidase (VP) with an enzyme activity recovery of about 79, 93, 27, and 27.5%, respectively. Similarly, the biocatalytic load of 116, 183, 23...
June 17, 2017: Environmental Science and Pollution Research International
Edman Shik Chi Tsang, Lin Ye, Ben Lo, Qi Song, Junlin Zheng, Dejing Kong, Claire A Murray, Chiu Tang
Here, we report a catalytic process of decarboxylating gamma-valerolactone, GVL (the biomass derived lactone as an example) over Zn/ZSM-5 to butene, followed by aromatization at high yield with co-feed water. Evaluation of catalytic performance at prolonged time shows that water molecule is essential in maintaining the decarboxylation/ aromatization activity without rapid deactivation. Synchrotron X-ray diffraction and Rietveld refinement are then used to elucidate the adsorbed structures of GVL and immobilized Zn-species with the support of EXAFS and NMR...
June 15, 2017: Angewandte Chemie
Kaiwen Chang, Zhihe Liu, Xiaofeng Fang, Haobin Chen, Xiaoju Men, Ye Yuan, Kai Sun, Xuanjun Zhang, Zhen Yuan, Changfeng Wu
Light has been widely used for cancer therapeutics such as photodynamic therapy (PDT) and photothermal therapy (PTT). This paper describes a strategy called enzyme-enhanced phototherapy (EEPT) for cancer treatment. We constructed a nanoparticle platform by covalent conjugation of glucose oxidase (GOx) to small polymer dots (Pdots), which could be persistently immobilized into tumor. While the malignant tumors have high glucose uptake, the GOx efficiently catalyzes the glucose oxidation with simultaneous generation of H2O2...
June 14, 2017: Nano Letters
Hossam Murad, Jana Mir Assaad, Rasha Al-Shemali, Abdul Qader Abbady
BACKGROUND: Monitoring blood levels of human growth hormone (hGH) in most children with short stature deficiencies is crucial for taking a decision of treatment with extended course of daily and expensive doses of recombinant hGH (rhGH or Somatropin(®)). Besides, misusing of rhGH by sportsmen is banned by the World Anti-Doping Agency and thus sensitive GH-detecting methods are highly welcome in this field. Nanobodies are the tiniest antigen-binding entity derived from camel heavy chain antibodies...
2017: Frontiers in Endocrinology
Vinod K Nigam, Tesnim Arfi, Vishal Kumar, Pratyoosh Shukla
Nitrilases are commercial biocatalysts used for the synthesis of plastics, paints, fibers in the chemical industries, pharmaceutical drugs and herbicides for agricultural uses. Nitrilase hydrolyses the nitriles and dinitriles to their corresponding carboxylic acids and ammonia. They have a broad range of substrate specificities as well as enantio-, regio- and chemo-selective properties which make them useful for biotransformation of nitriles to important compounds because of which they are considered as 'Green Catalysts'...
June 2017: Indian Journal of Microbiology
Ummirul Mukminin Kahar, Kok-Gan Chan, Mohd Helmi Sani, Nur Izzati Mohd Noh, Kian Mau Goh
Type I pullulanase from Anoxybacillus sp. SK3-4 (PulASK) is an unusual debranching enzyme that specifically hydrolyzes starch α-1,6 linkages at long branches producing oligosaccharides (≥G8), but is nonreactive against short branches; thus, incapable of producing reducing sugars (G1-G7). We report on the effects of both single and co-immobilization of PulASK on product specificity. PulASK was purified and immobilized through covalent attachment to three epoxides (ReliZyme EP403/M, Immobead IB-150P, and Immobead IB-150A) and an amino-epoxide (ReliZyme HFA403/M) activated supports...
June 10, 2017: International Journal of Biological Macromolecules
Jinlan Dong, Wenjing Ning, Weijing Liu, Merlin L Bruening
Proteolysis is often a critical step in protein characterization via mass spectrometry. Compared to complete digestion, limited proteolysis gives larger peptides, and the dominant cleavage sites may identify highly accessible, flexible protein regions. This paper explores controlled proteolysis in porous nylon membranes containing immobilized trypsin. Passage of protein solutions through ∼100 μm thick membranes provides reaction residence times as short as milliseconds to limit digestion. Additionally, variation of the membrane pore size and the protease-immobilization method (electrostatic adsorption or covalent anchoring to adsorbed polymer in membrane pores) affords control over the proteolysis rate...
June 13, 2017: Analyst
Christin Slomka, Georg Paris Späth, Phillip Lemke, Marc Skoupi, Christof M Niemeyer, Christoph Syldatk, Jens Rudat
The hydantoinase process is applied for the industrial synthesis of optically pure amino acids via whole cell biocatalysis, providing a simple and well-established method to obtain the catalyst. Nevertheless, whole cell approaches also bear disadvantages like intracellular degradation reactions, transport limitations as well as low substrate solubility. In this work the hydantoinase and carbamoylase from Arthrobacter crystallopoietes DSM 20117 were investigated with respect to their applicability in a cell-free hydantoinase process...
December 2017: AMB Express
T T K Nguyen, T T Vu, G Anquetin, H V Tran, S Reisberg, V Noël, G Mattana, Q V Nguyen, Tran Dai Lam, M C Pham, B Piro
We describe an electrochemical immunosensor based on functionalization of a working electrode by electrografting two functional diazonium salts. The first one is a molecular probe, diclofenac, coupled with an arylamine onto which a specific antibody is immobilized by affinity interactions; the second is a redox probe (a quinone) also coupled with an arylamine, able to transduce the hapten-antibody association into a change in electroactivity. The steric hindrance induced by the antibody leads to a current decrease upon binding of the antibody on the grafted molecular probe; conversely, when diclofenac is present in solution, a displacement equilibrium occurs between the target diffusing into the solution and the grafted probe...
June 7, 2017: Biosensors & Bioelectronics
Clarissa Müller, Dave Hartig, Karl Vorländer, Ann-Cathérine Sass, Stephan Scholl, Hans-Joachim Jördening
A hybrid-immobilization method was developed to improve the long-term stability of laminaribiose phosphorylase immobilized on epoxy supports Sepabeads EC-EP/S. Entrapment in chitosan retained all of the enzyme activity depending on the amount of entrapped solid materials and increased half-life by a factor of 10-94.4 h. No enzyme activity loss was determined during 12 times reuse. The immobilization method is also applicable to sucrose phosphorylase immobilized on Sepabeads EC-EP/S. Up to 31.9 g/L laminaribiose were produced in bienzymatic batch experiments with reaction-integrated product separation by adsorption on zeolites...
June 10, 2017: Bioprocess and Biosystems Engineering
Gabriella Sanzò, Irene Taurino, Francesca Puppo, Riccarda Antiochia, Lo Gorton, Gabriele Favero, Franco Mazzei, Sandro Carrara, Giovanni De Micheli
In this work, we have developed for the first time a method to make novel gold and platinum hybrid bimetallic nanostructures differing in shape and size. Au-Pt nanostructures were prepared by electrodeposition in two simple steps. The first step consists of the electrodeposition of nanocoral Au onto a gold substrate using hydrogen as a dynamic template in an ammonium chloride solution. After that, the Pt nanostructures were deposited onto the nanocoral Au organized in pores. Using Pt (II) and Pt (IV), we realized nanocoral Au decorated with Pt nanospheres and nanocoral Au decorated with Pt nanoflowers, respectively...
June 6, 2017: Methods: a Companion to Methods in Enzymology
Muhammad Irshad, Aimen Murtza, Muddassar Zafar, Khizar Hayat Bhatti, Abdul Rehman, Zahid Anwar
Biological macromolecules are primarily composed of complex polysaccharides that strengthen microbial growth for the production of industrially relevant enzymes. The presence of polysaccharides in the form of the disrupted cell wall and cell materials are among major challenges in the fruit juice industry. The breakdown of such biological macromolecules including cellulose and pectin is vital for the juices processing. In this background, pectinolytic enzymes including polygalacturonase (PG), pectin lyase (PL), and pectin methylesterase (PME) were isolated from Aspergillus ornatus, statistically optimized and purified via ammonium sulfate fractionation (ASF), dialysis, and Sephadex G-100 gel permeation chromatography...
June 7, 2017: International Journal of Biological Macromolecules
Zongbao Chen, Minghua Lu
A new magneto-controlled electrochemical immunosensing system was developed for the sensitive detection of low-abundance protein (IgG1 used in this case) with a sandwich-type assay format on monoclonal mouse anti-human Fab-specific IgG1-functionalized magnetic bead. Metal sulfide (CdS) quantum dot-doped bovine serum albumin (QD-BSA) was synthesized and functionalized with monoclonal Fc-specific anti-human antibody. In the presence of IgG1, the immobilized antibody on magnetic bead was selective to capture the Fab region of the analyte, followed to be sandwiched by the conjugated antibody onto QD-BSA...
August 1, 2017: Analytica Chimica Acta
Lu Fang, Bo Liang, Guang Yang, Yichuan Hu, Qin Zhu, Xuesong Ye
A minimally invasive glucose biosensor capable of continuous monitoring of subcutaneous glucose has been developed in this study. This sensor was prepared using electropolymerized conductive polymer polyaniline (PANI) nanofibers as an enzyme immobilization material and polyurethane (PU)/epoxy-enhanced polyurethane (E-PU) bilayer coating as a protective membrane. The sensor showed almost the same sensitivity (63nA/mM) and linearity (0-20mM with the correlation coefficient r(2) of 0.9997) in both PBS and bovine serum tests...
April 28, 2017: Biosensors & Bioelectronics
Hyun Jong Lee, Gabriella Fernandes-Cunha, Ilham Putra, Won-Gun Koh, David Myung
Surface modifications with tethered growth factors have mainly been applied to synthetic polymeric biomaterials in well-controlled, acellular settings, followed by seeding with cells. The known bio-orthogonality of copper-free click chemistry provides an opportunity to not only use it in vitro to create scaffolds or pro-migratory tracks in the presence of living cells, but also potentially apply it to living tissues directly as a coupling modality in situ. In this study, we studied the chemical coupling of growth factors to collagen using biocompatible copper-free click chemistry and its effect on the enhancement of growth factor activity in vitro...
June 9, 2017: ACS Applied Materials & Interfaces
Fetch more papers »
Fetching more papers... Fetching...
Read by QxMD. Sign in or create an account to discover new knowledge that matter to you.
Remove bar
Read by QxMD icon Read

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"