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1.
Phys Chem Chem Phys ; 23(36): 20709-20717, 2021 Sep 22.
Artigo em Inglês | MEDLINE | ID: mdl-34516596

RESUMO

It is usually assumed that enzymes retain their native structure during catalysis. However, the aggregation and fragmentation of proteins can be difficult to detect and sometimes conclusions are drawn based on the assumption that the protein is in its native form. We have examined three model enzymes, alkaline phosphatase (AkP), hexokinase (HK) and glucose oxidase (GOx). We find that these enzymes aggregate or fragment after addition of chemical species directly related to their catalysis. We used several independent techniques to study this behavior. Specifically, we found that glucose oxidase and hexokinase fragment in the presence of D-glucose but not L-glucose, while hexokinase aggregates in the presence of Mg2+ ion and either ATP or ADP at low pH. Alkaline phosphatase aggregates in the presence of Zn2+ ion and inorganic phosphate. The aggregation of hexokinase and alkaline phosphatase does not appear to attenuate their catalytic activity. Our study indicates that specific multimeric structures of native enzymes may not be retained during catalysis and suggests pathways for different enzymes to associate or separate over the course of substrate turnover.


Assuntos
Fosfatase Alcalina/química , Glucose Oxidase/química , Hexoquinase/química , Fosfatase Alcalina/metabolismo , Biocatálise , Glucose Oxidase/metabolismo , Hexoquinase/metabolismo , Modelos Moleculares , Estrutura Molecular , Agregados Proteicos
2.
ACS Appl Mater Interfaces ; 13(33): 39719-39729, 2021 Aug 25.
Artigo em Inglês | MEDLINE | ID: mdl-34392680

RESUMO

In this work, cucurbiturils (CBs), a class of macrocyclic supramolecules, were observed to have an interesting peroxidase-like activity, which is metal-free, substrate-specific, thermophilic, acidophilic, and insensitive to ionic strength. By coating CBs on enzyme-encapsulated zeolitic imidazolate framework-8 (ZIF-8), a composite nanozyme was constructed, which retains the catalytic ability of CBs and enzymes and makes them cascade. On addition of the substrate, i.e., the detection target, a highly efficient cascade catalysis can be launched in all the spatial directions to generate sensitive and visible signals. Convenient detection of glucose and cholesterol as models is thereby achieved. More importantly, we have also successfully constructed a composite nanozyme-based sensor array (6 × 8 wells) and thereby achieved simultaneous colorimetric analysis of multiple samples. The concept and successful practice of the construction of the unique core-shell supramolecule/biomolecule@nanomaterial architecture provide the possibility to fabricate next-generation multifunctional materials and create new applications by integrating their unique functions.


Assuntos
Hidrocarbonetos Aromáticos com Pontes/química , Imidazóis/química , Nanocompostos/química , Peroxidases/química , Zeolitas/química , Técnicas Biossensoriais , Hidrocarbonetos Aromáticos com Pontes/metabolismo , Catálise , Colorimetria , Corantes Fluorescentes/química , Glucose Oxidase/química , Glucose Oxidase/metabolismo , Peróxido de Hidrogênio/química , Imidazóis/metabolismo , Simulação de Acoplamento Molecular , Oxirredução , Peroxidases/metabolismo , Impressão Tridimensional
3.
Molecules ; 26(12)2021 Jun 20.
Artigo em Inglês | MEDLINE | ID: mdl-34203057

RESUMO

A biosensing membrane base on ferulic acid and glucose oxidase is synthesized onto a carbon paste electrode by electropolymerization via cyclic voltammetry in aqueous media at neutral pH at a single step. The developed biosensors exhibit a linear response from 0.082 to 34 mM glucose concentration, with a coefficient of determination R2 equal to 0.997. The biosensors display a sensitivity of 1.1 µAmM-1 cm-2, a detection limit of 0.025 mM, and 0.082 mM as glucose quantification limit. The studies reveal stable, repeatable, and reproducible biosensors response. The results indicate that the novel poly-ferulic acid membrane synthesized by electropolymerization is a promising method for glucose oxidase immobilization towards the development of glucose biosensors. The developed glucose biosensors exhibit a broader linear glucose response than other polymer-based glucose biosensors.


Assuntos
Técnicas Biossensoriais/métodos , Carbono/química , Ácidos Cumáricos/química , Técnicas Eletroquímicas/métodos , Glucose Oxidase/metabolismo , Glucose/análise , Polímeros/química , Técnicas Biossensoriais/normas , Eletrodos , Enzimas Imobilizadas , Glucose Oxidase/química , Limite de Detecção
4.
ACS Appl Mater Interfaces ; 13(27): 31514-31526, 2021 Jul 14.
Artigo em Inglês | MEDLINE | ID: mdl-34213305

RESUMO

Micro/nanomotors (MNMs), which propel by transforming various forms of energy into kinetic energy, have emerged as promising therapeutic nanosystems in biomedical applications. However, most MNMs used for anticancer treatment are only powered by one engine or provide a single therapeutic strategy. Although double-engined micromotors for synergistic anticancer therapy can achieve more flexible movement and efficient treatment efficacy, their design remains challenging. In this study, we used a facile preparation method to develop enzymatic/magnetic micromotors for synergetic cancer treatment via chemotherapy and starvation therapy (ST), and the size of micromotors can be easily regulated during the synthetic process. The enzymatic reaction of glucose oxidase, which served as the chemical engine, led to self-propulsion using glucose as a fuel and ST via a reduction in the energy available to cancer cells. Moreover, the incorporation of Fe3O4 nanoparticles as a magnetic engine enhanced the kinetic power and provided control over the direction of movement. Inherent pH-responsive drug release behavior was observed owing to the acidic decomposition of drug carriers in the intracellular microenvironment of cancer cells. This system displayed enhanced anticancer efficacy owing to the synergetic therapeutic strategies and increased cellular uptake in a targeted area because of the improved motion behavior provided by the double engines. Therefore, the demonstrated micromotors are promising candidates for anticancer biomedical microsystems.


Assuntos
Glucose Oxidase/metabolismo , Fenômenos Magnéticos , Microtecnologia/métodos , Neoplasias/terapia , Linhagem Celular Tumoral , Portadores de Fármacos/química , Humanos , Espaço Intracelular/efeitos dos fármacos , Espaço Intracelular/metabolismo , Nanopartículas de Magnetita/química , Neoplasias/tratamento farmacológico , Neoplasias/patologia
5.
Biomaterials ; 275: 120927, 2021 08.
Artigo em Inglês | MEDLINE | ID: mdl-34119887

RESUMO

Early antitumor therapy is an important determinant of survival in patients with cancer. Utilization of specific pathological states, such as hypoxia, greatly promotes the development of intelligent drug delivery systems (DDSs) for targeted antitumor therapy. However, a slight decrease in oxygen levels in early-stage tumors is not sufficient to trigger hypoxia-responsive drug release. Nitroreductase (NTR) is overexpressed in bioreductive hypoxic cancers, and its expression level has been verified to be directly related to hypoxic status. Herein, using glucose oxidase (GOx) as an O2-consuming agent to exacerbate hypoxia, a cascade strategy of GOx-induced overexpression of NTR and amplified NTR-catalyzed release was proposed for early antitumor therapy. Briefly, NTR-sensitive p-nitrobenzyl chloroformate (PNZ-Cl) was adopted to conjugate with the polysaccharide chitosan (CS) and self-assemble into CS-PNZ-Cl micelles. These polymer micelles possess the dual abilities to specifically immobilize GOx and load mitoxantrone (MIT) to form the NTR-responsive nanocascade reactor GOx/MIT@CS-PNZ-Cl. First, as a "key", tumor hypoxia triggers the initial release of GOx, which serves as the O2-consuming agent when catalyzing its reaction with glucose, which is accompanied by H2O2 production. Depleted oxygen levels facilitate the expression of NTR, which in turn amplifies the capacity of the nanocascade reactor to decompose into secondary micelles for enhanced intratumoral permeation. GOx-inspired NTR amplification further elicits MIT release, realizing a synergistic "domino effect" cascade. In addition, upregulated H2O2 has been shown to effectively reverse GSH-mediated MIT resistance, reaching the superior tumor inhibition rate of 93.08%. This GOx-based NTR-responsive nanocascade reactor provides amplification of the bioreductive hypoxic tumor microenvironment for early antitumor therapy.


Assuntos
Glucose Oxidase , Peróxido de Hidrogênio , Neoplasias/tratamento farmacológico , Liberação Controlada de Fármacos , Resistência a Múltiplos Medicamentos , Resistencia a Medicamentos Antineoplásicos , Glucose Oxidase/metabolismo , Humanos , Nitrorredutases/genética
6.
Biomaterials ; 275: 120987, 2021 08.
Artigo em Inglês | MEDLINE | ID: mdl-34175561

RESUMO

Hydroxyl radical (·OH)-mediated chemodynamic therapy (CDT) and glucose oxidase (GOx)-based starvation therapy (ST) are two emerging antitumor strategies, limited by acid/H2O2 deficiency and tumor hypoxia, respectively. Herein, we developed a liposomal nanoplatform co-delivering Fe(OH)3-doped CaO2 nanocomposites and GOx molecules for synergistic CDT/ST with a complementary effect. Based on Fenton reactions initiated by iron ions, CaO2-supplied H2O2 could not only generate ·OH for H2O2-sufficient CDT, but also produce O2 to promote the catalytic efficiency of GOx under hypoxia. In return, the enhanced ST generated gluconic acid and H2O2, further amplifying CDT. Through in vitro and in vivo experiments, we demonstrated that such a mutually reinforced modality based on the cyclic Fenton/starvation reactions provided a novel and potent anticancer mechanism for the effective treatment of hypoxic cancers.


Assuntos
Peróxido de Hidrogênio , Neoplasias , Catálise , Linhagem Celular Tumoral , Glucose Oxidase/metabolismo , Humanos , Neoplasias/tratamento farmacológico , Hipóxia Tumoral
7.
ACS Appl Mater Interfaces ; 13(21): 24532-24542, 2021 Jun 02.
Artigo em Inglês | MEDLINE | ID: mdl-34019368

RESUMO

Sonodynamic therapy (SDT) is a promising method for tumor treatment, but self-quenching property, low loading efficiency of sonosensitizers, and hypoxia tumor microenvironment (TME) hinder the efficiency of SDT. Herein, an erythrocyte membrane (EM)-camouflaged metal-organic framework (MOF) of PCN-224 nanoparticles (NPs) integrated with platinum (Pt) NPs as well as glucose oxidase (GOx) has been developed to overcome these limits. Porphyrin-based PCN-224 NPs are synthesized as a sonosensitizer with a large amount of well-organized porphyrin molecules while simultaneously acting as the nanocarriers (NCs) for Pt NPs and GOx. When the NCs are internalized by tumor cells, Pt NPs on their surface are able to utilize endogenous hydrogen peroxide (H2O2) to produce oxygen for the relief of tumor hypoxia, thus enhancing the SDT effect. After EM cloaking, the longer circulation time can improve biocompatibility in vivo and enhance accumulation in tumor tissue. Loaded GOx is beneficial to local glucose consumption and can realize the tumor starvation therapy effect. Consequently, these multifunctional NCs show amplified synergistic therapeutic effects of tumor SDT and starvation therapy, which can efficiently inhibit the tumor growth.


Assuntos
Portadores de Fármacos , Membrana Eritrocítica , Glucose Oxidase/metabolismo , Nanopartículas Metálicas/administração & dosagem , Neoplasias/tratamento farmacológico , Platina/química , Hipóxia Tumoral , Terapia por Ultrassom , Animais , Terapia Combinada , Nanopartículas Metálicas/química , Camundongos , Camundongos Endogâmicos ICR , Neoplasias/patologia , Neoplasias/terapia , Ensaios Antitumorais Modelo de Xenoenxerto
9.
Chem Commun (Camb) ; 57(44): 5438-5441, 2021 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-33949484

RESUMO

An artificial protocell model mimicking stimuli-triggered extracellular matrix formation is demonstrated based on the self-immobilization of coacervate microdroplets. Endogenous enzyme activity within the microdroplets results in the release of Ca2+ ions that trigger hydrogelation throughout the external environment, which in turn mechanically supports and chemically stabilizes the protocells.


Assuntos
Glucose Oxidase/metabolismo , Cálcio/química , Cálcio/metabolismo , Géis/química , Géis/metabolismo , Glucose Oxidase/química , Tamanho da Partícula
10.
ACS Appl Mater Interfaces ; 13(23): 26704-26711, 2021 Jun 16.
Artigo em Inglês | MEDLINE | ID: mdl-34038080

RESUMO

Monitoring glucose levels in physiological fluids can help prevent severe complications associated with hypo- and hyper-glycemic events. Current glucose-monitoring systems require a three-electrode setup and a power source to function, which can hamper the system miniaturization to the patient discomfort. Enzymatic fuel cells (EFCs) offer the opportunity to develop self-powered and minimally invasive glucose sensors by eliminating the need for an external power source. Nevertheless, practical applications demand for cost-effective and mass-manufacturable EFCs compatible with integration strategies. In this study, we explore for the first time the use of gold electrodes on a printed circuit board (PCB) for the development of an EFC and demonstrate its application in saliva. To increase the specific surface area, the PCB gold-plated electrodes were modified with porous gold films. At the anode, glucose oxidase is immobilized with an osmium redox polymer that serves as an electron-transfer mediator. At the cathode, bilirubin oxidase is adsorbed onto the porous gold surface with a blocking agent that prevents parasitic reactions while maintaining the enzyme catalytic activity. The resulting EFC showed a linear response to glucose in phosphate buffer within the range 50 µM to 1 mM, with a sensitivity of 14.13 µA cm-2 mM-1. The sensor was further characterized in saliva, showing the linear range of detection of 0.75 to 2 mM, which is within the physiological range, and sensitivity of 21.5 µA cm-2 mM-1. Overall, this work demonstrates that PCBs are suitable platforms for EFCs, paving the way for the development of fully integrated systems in a seamless and miniaturized device.


Assuntos
Técnicas Biossensoriais/métodos , Eletrodos , Enzimas Imobilizadas/metabolismo , Glucose Oxidase/metabolismo , Glucose/análise , Oxigênio/metabolismo , Saliva/metabolismo , Fontes de Energia Bioelétrica , Catálise , Enzimas Imobilizadas/química , Humanos , Saliva/química
11.
Soft Matter ; 17(20): 5240-5247, 2021 May 26.
Artigo em Inglês | MEDLINE | ID: mdl-33949590

RESUMO

Redox mediators are pivotal players in the electron transfer process between enzymes and electrodes. We present an alternative approach for redox mediation based on branched polyethyleneimine (BPEI) modified with an osmium complex. This redox polyelectrolyte is crosslinked with phosphate to produce colloidal particles with a diameter of ca. 1 µm, which, combined with glucose oxidase (GOx), can form electroactive assemblies through either layer by layer assembly (LbL) or one-pot drop-casting (OPDC). The addition of NaCl to these colloidal systems induces the formation of films that otherwise poorly grow, presenting an outstanding catalytic current. The system was tested as a bioanode delivering a power output of 148 µW per nmol of mediator. These results are explained in terms of the interactions of the ions with the polyelectrolyte and represent a new route for the development of bioelectrochemical devices involving redox mediators and enzymes.


Assuntos
Fontes de Energia Bioelétrica , Eletrodos , Enzimas Imobilizadas/metabolismo , Glucose , Glucose Oxidase/metabolismo , Oxirredução , Polieletrólitos
12.
J Mater Chem B ; 9(18): 3885-3891, 2021 05 12.
Artigo em Inglês | MEDLINE | ID: mdl-33928327

RESUMO

Glucose detection is a crucial topic in the diagnosis of numerous diseases, such as hypoglycemia or diabetes mellitus. Research indicates that people with diabetes mellitus are at a higher risk of developing various types of cancer. A nanoplatform that combines both diabetes diagnosis and cancer therapy might be regarded as a more effective way to solve the above-mentioned problem. However, none of the known sensors has a smart strategy that can work as a fluorescent glucose sensor and a cancer therapeutic platform simultaneously. Here, we developed a pH responsive biomimetic-mineralized nanoplatform (denoted as CaCO3-PDA@DOX-GOx) for glucose detection in serum samples and applied it to treat the tumor cells combined chemotherapy with the starvation therapy in vitro. Doxorubicin (DOX) and glucose oxidase (GOx) were loaded through the mesoporous CaCO3-PDA nanoparticles (m-CaCO3-PDA NPs). The fluorescence of DOX is quenched as a result of fluorescence resonance energy transfer (FRET) caused by the broad absorption of m-CaCO3-PDA NPs. The nanoplatform would recover fluorescence under lower pH values due to the catalytic reaction of GOx with glucose or tumor microenvironment (TME), which leads to the elimination of FRET. Its application as a glucose sensor is indicated with a linear relationship in the range of 0.01-1.0 mM of glucose and limit of detection is calculated by 6 µM. This nanoplatform also has a TME-responsive antitumor effect and fluorescence imaging functionality, which provide a new idea for cancer therapy together with glucose monitoring in diabetes.


Assuntos
Materiais Biomiméticos/química , Glicemia/análise , Nanopartículas/química , Materiais Biomiméticos/síntese química , Materiais Biomiméticos/farmacologia , Carbonato de Cálcio/química , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Doxorrubicina/química , Doxorrubicina/farmacologia , Glucose Oxidase/química , Glucose Oxidase/metabolismo , Humanos , Concentração de Íons de Hidrogênio , Indóis/química , Microscopia Confocal , Polímeros/química , Porosidade
13.
J Mater Chem B ; 9(16): 3509-3514, 2021 04 28.
Artigo em Inglês | MEDLINE | ID: mdl-33909733

RESUMO

Early glucose detection is important in both healthy people and diabetic patients. The glucose colorimetric detection techniques usually consist of multiple steps and their preparation processes are time consuming. In this work, we fabricate a GOX-hemin nanogel (GHN) that could be used for one-step colorimetry detection of glucose. The GHN was prepared by carrying out polymerization on the surface of GOX. Each GOX-hemin nanogel consists of a single GOX encapsulated with a thin polymer network containing hemin. The proximity of hemin to GOX facilitates two reactions, i.e. the oxidation of glucose catalysed by GOX to yield H2O2, and the subsequent 3,3',5,5'-tetramethylbenzidine (TMB) oxidation reaction catalysed by hemin to yield the blue colored product. These processes work in tandem, which greatly enhances the efficacy, sensitivity and stability of the detection system. The limit of detection in our system was determined to be as low as 4 µM. Furthermore, the glucose detection activity still maintained more than 70% even after being incubated at 55 °C for 30 minutes, or in 20% (v/v) aqueous solution of DMF, CH3CN or THF for 25 minutes at room temperature. It is anticipated that this work can provide a method for developing diverse functional materials based on proteins.


Assuntos
Glucose Oxidase/química , Glucose/análise , Hemina/química , Nanogéis/química , Glucose Oxidase/metabolismo , Hemina/metabolismo , Humanos , Estrutura Molecular , Tamanho da Partícula
14.
ACS Appl Mater Interfaces ; 13(15): 17289-17299, 2021 Apr 21.
Artigo em Inglês | MEDLINE | ID: mdl-33827209

RESUMO

Bacterial/fungal biofilm-mediated persistent endodontic infections (PEIs) are one of the most frequent clinical lesions in the oral cavity, resulting in apical periodontitis and tooth damage caused by loss of minerals. The conventional root canal disinfectants are poorly bio-safe and harmful to teeth and tissues, making them ineffective in treating PEIs. The development of nanomaterials is emerging as a promising strategy to eradicate disease-related bacteria/fungi. Herein, glucose oxidase (GOx)-modified magnetic nanoparticles (MNPs) were synthesized via a facile and versatile route for investigating their effects on removing PEI-related bacterial/fungal biofilms. It is found that GOx was successfully immobilized on the MNPs by detecting the changes in the diameter, chemical functional group, charge, and magnetic response. Further, we demonstrate that GOx-modified MNPs (GMNPs) exhibit highly effective antibacterial activity against Enterococcus faecalis and Candida albicans. Moreover, the antibacterial/fungal activity of GMNPs is greatly dependent on their concentrations. Importantly, when placed in contact with bacterial/fungal biofilms, the dense biofilm matrix is destructed due to the movement of GMNPs induced by the magnetic field, the formation of reactive oxygen species, and nutrient starvation induced by GOx. Also, the in vitro experiment shows that the as-prepared GMNPs have excellent cytocompatibility and blood compatibility. Thus, GMNPs offer a novel strategy to treat bacteria/fungi-associated PEIs for potential clinical applications.


Assuntos
Materiais Biocompatíveis/farmacologia , Biofilmes/efeitos dos fármacos , Polpa Dentária/efeitos dos fármacos , Polpa Dentária/microbiologia , Glucose Oxidase/metabolismo , Imãs/química , Nanopartículas/química , Materiais Biocompatíveis/química , Candida albicans/efeitos dos fármacos , Enterococcus faecalis/efeitos dos fármacos , Teste de Materiais , Espécies Reativas de Oxigênio/metabolismo
15.
J Colloid Interface Sci ; 594: 874-881, 2021 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-33794409

RESUMO

The hybridization of enzymes and inorganics in controlled manner is challenging, however, critical for the development of chemo-enzymatic cascade catalyst with high efficiency and selectivity. Here, proteins and metal oxide clusters can be facilely co-assembled on the surface of colloid of poly(4-vinylpyridine) (P4VP) via hydrogen bonding, due to their enriched surface hydrogen bonding donors. The co-assembly method can be generally applied for preparing chemo-enzymatic catalyst within the selected database of various proteins and metal oxide clusters while the assembly units retain their structures and activities. Typically, a 2.5 nm metal oxide cluster {Mo72Fe30}, with peroxidase-like activity, are complexed with glucose oxidase (GOX) on P4VP for the catalysis against the oxidization of o-dianisidine (ODA) with the existence of glucose. Due to the synergistic effects of chemical and enzymatic catalysis, the co-assemblies show even higher ODA oxidation activity compared to GOX/catalase bi-enzymatic system, confirming the effectiveness of the co-assembly protocol for cascade catalysis and enabling its applications in rapid glucose detection and biomass conversion.


Assuntos
Glucose Oxidase , Polímeros , Catálise , Glucose Oxidase/metabolismo , Oxirredução , Óxidos
16.
Acc Chem Res ; 54(7): 1779-1790, 2021 04 06.
Artigo em Inglês | MEDLINE | ID: mdl-33751886

RESUMO

Atom-transfer radical polymerization (ATRP) is a well-known technique for the controlled polymerization of vinyl monomers under mild conditions. However, as with any other radical polymerization, ATRP typically requires rigorous oxygen exclusion, making it time-consuming and challenging to use by nonexperts. In this Account, we discuss various approaches to achieving oxygen tolerance in ATRP, presenting the overall progress in the field.Copper-mediated ATRP, which we first discovered in the late 1990s, uses a CuI/L activator that reversibly reacts with the dormant C(sp3)-X polymer chain end, forming a X-CuII/L deactivator and a propagating radical. Oxygen interferes with activation and chain propagation by quenching the radicals and oxidizing the activator. At ATRP equilibrium, the activator is present at a much higher concentration than the propagating radicals. Thus, oxidation of the activator is the dominant inhibition pathway. In conventional ATRP, this reaction is irreversible, so oxygen must be strictly excluded to achieve good results.Over the last two decades, our group has developed several ATRP techniques based on the concept of regenerating the activator. When the oxidized activator is continuously converted back to its active reduced form, then the catalytic system itself can act as an oxygen scavenger. Regeneration can be accomplished by reducing agents and photo-, electro-, and mechanochemical stimuli. This family of methods offers a degree of oxygen tolerance, but most of them can tolerate only a limited amount of oxygen and do not allow polymerization in an open vessel.More recently, we discovered that enzymes can be used in auxiliary catalytic systems that directly deoxygenate the reaction medium and protect the polymerization process. We developed a method that uses glucose oxidase (GOx), glucose, and sodium pyruvate to very effectively scavenge oxygen and enable open-vessel ATRP. By adding a second enzyme, horseradish peroxidase (HPR), we managed to extend the role of the auxiliary enzymatic system to generating carbon-based radicals and changed ATRP from an oxygen-sensitive to an oxygen-fueled reaction.While performing control experiments for the enzymatic methods, we noticed that using sodium pyruvate under UV irradiation triggers polymerization without the presence of GOx. This serendipitous discovery allowed us to develop the first oxygen-proof, small-molecule-based, photoinduced ATRP system. It has oxygen tolerance similar to that of the enzymatic methods, exhibits superior compatibility with both aqueous media and organic solvents, and avoids problems associated with purifying polymers from enzymes. The system was able to rapidly polymerize N-isopropylacrylamide, a challenging monomer, with a high degree of control.These contributions have substantially simplified the use of ATRP, making it more practical and accessible to everyone.


Assuntos
Oxigênio/metabolismo , Radicais Livres/química , Radicais Livres/metabolismo , Glucose/química , Glucose/metabolismo , Glucose Oxidase/química , Glucose Oxidase/metabolismo , Peroxidase do Rábano Silvestre/química , Peroxidase do Rábano Silvestre/metabolismo , Oxirredução , Oxigênio/química , Polimerização , Ácido Pirúvico/química , Ácido Pirúvico/metabolismo
17.
Photochem Photobiol Sci ; 20(3): 369-378, 2021 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-33721272

RESUMO

Tryptophan and tyrosine radical intermediates play crucial roles in many biological charge transfer processes. Particularly in flavoprotein photochemistry, short-lived reaction intermediates can be studied by the complementary techniques of ultrafast visible and infrared spectroscopy. The spectral properties of tryptophan radical are well established, and the formation of neutral tyrosine radicals has been observed in many biological processes. However, only recently, the formation of a cation tyrosine radical was observed by transient visible spectroscopy in a few systems. Here, we assigned the infrared vibrational markers of the cationic and neutral tyrosine radical at 1483 and 1502 cm-1 (in deuterated buffer), respectively, in a variant of the bacterial methyl transferase TrmFO, and in the native glucose oxidase. In addition, we studied a mutant of AppABLUF blue-light sensor domain from Rhodobacter sphaeroides in which only a direct formation of the neutral radical was observed. Our studies highlight the exquisite sensitivity of transient infrared spectroscopy to low concentrations of specific radicals.


Assuntos
Flavoproteínas/química , Radicais Livres/química , Espectrofotometria Infravermelho , Tirosina/química , Proteínas de Bactérias/química , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Cátions/química , Flavoproteínas/metabolismo , Glucose Oxidase/química , Glucose Oxidase/metabolismo , Metiltransferases/química , Metiltransferases/genética , Metiltransferases/metabolismo , Mutagênese Sítio-Dirigida , Complexo de Proteínas do Centro de Reação Fotossintética/química , Complexo de Proteínas do Centro de Reação Fotossintética/genética , Complexo de Proteínas do Centro de Reação Fotossintética/metabolismo , Proteínas Recombinantes/biossíntese , Proteínas Recombinantes/química , Proteínas Recombinantes/isolamento & purificação , Rhodobacter sphaeroides/metabolismo
18.
Nat Commun ; 12(1): 1898, 2021 03 26.
Artigo em Inglês | MEDLINE | ID: mdl-33772017

RESUMO

Triplet-triplet annihilation upconversion nanoparticles have attracted considerable interest due to their promises in organic chemistry, solar energy harvesting and several biological applications. However, triplet-triplet annihilation upconversion in aqueous solutions is challenging due to sensitivity to oxygen, hindering its biological applications under ambient atmosphere. Herein, we report a simple enzymatic strategy to overcome oxygen-induced triplet-triplet annihilation upconversion quenching. This strategy stems from a glucose oxidase catalyzed glucose oxidation reaction, which enables rapid oxygen depletion to turn on upconversion in the aqueous solution. Furthermore, self-standing upconversion biological sensors of such nanoparticles are developed to detect glucose and measure the activity of enzymes related to glucose metabolism in a highly specific, sensitive and background-free manner. This study not only overcomes the key roadblock for applications of triplet-triplet annihilation upconversion nanoparticles in aqueous solutions, it also establishes the proof-of-concept to develop triplet-triplet annihilation upconversion nanoparticles as background free self-standing biological sensors.


Assuntos
Glucose Oxidase/metabolismo , Glucose/metabolismo , Nanopartículas/química , Oxigênio/química , Algoritmos , Catálise/efeitos da radiação , Humanos , Luz , Modelos Químicos , Estrutura Molecular , Nanopartículas/efeitos da radiação , Oxirredução/efeitos da radiação , Oxigênio/metabolismo , Espectrometria de Fluorescência , Água/química
19.
J Biotechnol ; 328: 106-114, 2021 Feb 20.
Artigo em Inglês | MEDLINE | ID: mdl-33485863

RESUMO

A novel glucose oxidase (GOD)-perhydrolase-in situ chemical oxidation (ISCO) cascade reaction system was designed, optimized, and verified the operation feasibility in this research. Among the determined four perhydrolases, acyltransferase from Mycobacterium smegmatis (MsAcT) displayed the highest specific activity for perhydrolysis reaction (76.4 U/mg) and the lowest Km value to hydrogen peroxide (13.9 mmol/L). GOD-MsAcT cascade reaction system also displayed high catalytic efficiency. Under the optimal parameters (50:1 activity unit ratio of GOD to MsAcT, pH 8.0, 50 mmol/L of ß-d-glucose, and 15 mmol/L of glyceryl triacetate), the melanin decolorization rate using GOD-MsAcT-ISCO cascade reaction system reached 86.8 %. Kinetics of GOD-MsAcT-ISCO cascade reaction system for melanin decolorization fitted the kinetic model of Boltzmann sigmoid. As a substitutive skin whitening technology, GOD-MsAcT-ISCO cascade reaction system displayed an excellent application prospect.


Assuntos
Glucose Oxidase , Melaninas , Catálise , Glucose Oxidase/metabolismo , Cinética , Melaninas/metabolismo , Oxirredução
20.
Biosensors (Basel) ; 11(1)2021 Jan 07.
Artigo em Inglês | MEDLINE | ID: mdl-33430194

RESUMO

Biofuel cells allow for constructing sensors that leverage the specificity of enzymes without the need for an external power source. In this work, we design a self-powered glucose sensor based on a biofuel cell. The redox enzymes glucose dehydrogenase (NAD-GDH), glucose oxidase (GOx), and horseradish peroxidase (HRP) were immobilized as biocatalysts on the electrodes, which were previously engineered using carbon nanostructures, including multi-wall carbon nanotubes (MWCNTs) and reduced graphene oxide (rGO). Additional polymers were also introduced to improve biocatalyst immobilization. The reported design offers three main advantages: (i) by using glucose as the substrate for the both anode and cathode, a more compact and robust design is enabled, (ii) the system operates under air-saturating conditions, with no need for gas purge, and (iii) the combination of carbon nanostructures and a multi-enzyme cascade maximizes the sensitivity of the biosensor. Our design allows the reliable detection of glucose in the range of 0.1-7.0 mM, which is perfectly suited for common biofluids and industrial food samples.


Assuntos
Técnicas Biossensoriais/instrumentação , Enzimas Imobilizadas/metabolismo , Glucose/análise , Nanotubos de Carbono/química , Biocatálise , Fontes de Energia Bioelétrica , Eletrodos , Enzimas Imobilizadas/química , Glucose 1-Desidrogenase/química , Glucose 1-Desidrogenase/metabolismo , Glucose Oxidase/química , Glucose Oxidase/metabolismo , Grafite/química , Peroxidase do Rábano Silvestre/química
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