- Enhanced Activity of Enzymes Encapsulated in Hydrophilic Metal-Organic Frameworks
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Encapsulation of biomacromolecules in metal-organic frameworks (MOFs) can preserve biological functionality in harsh environments. Despite the success of this approach, termed biomimietic mineralization, limited consideration has been given to the chemistry of the MOF coating. Here, we show that enzymes encapsulated within hydrophilic MAF-7 or ZIF-90 retain enzymatic activity upon encapsulation and when exposed to high temperatures, denaturing or proteolytic agents, and organic solvents, whereas hydrophobic ZIF-8 affords inactive catalase and negligible protection to urease.
- Liang, Weibin,Xu, Huoshu,Carraro, Francesco,Maddigan, Natasha K.,Li, Qiaowei,Bell, Stephen G.,Huang, David M.,Tarzia, Andrew,Solomon, Marcello B.,Amenitsch, Heinz,Vaccari, Lisa,Sumby, Christopher J.,Falcaro, Paolo,Doonan, Christian J.
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- Post-synthetic transformation of a Zn(II) polyhedral coordination network into a new supramolecular isomer of HKUST-1
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A Zn-based porphyrin containing metal-organic material (porphMOM-1) was transformed into a novel Cu-based porphyrin-encapsulating metal-organic material (porph@HKUST-1-β) via a one-pot post-synthetic modification (PSM) process involving both metal ion exchange and linker installation of trimesic acid. HKUST-1-β is the first example of yao topology and is to our knowledge the first supramolecular isomer of the archetypal coordination network HKUST-1.
- Chen, Yao,Wojtas, Lukasz,Ma, Shengqian,Zaworotko, Michael J.,Zhang, Zhenjie
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- A low molecular weight hydrogel which exhibits electroosmotic flow and its use as a bioreactor and for electrochromatography of neutral species
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A low molecular weight hydrogel which exhibits electroosmotic flow is described, and its use for separation and biocatalytic applications that require passage of a solvent stream through the gel is demonstrated. The Royal Society of Chemistry.
- Mizrahi, Shaul,Rizkov, Dan,Hayat, Netanel,Lev, Ovadia
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- Mimicking peroxidase activity by a polymer-supported oxidovanadium(IV) Schiff base complex derived from salicylaldehyde and 1,3-diamino-2-hydroxypropane
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The polymer-supported oxidovanadium(IV) complex PS-[VIVO(sal-dahp)] (2) (PS = chloromethylated polystyrene crosslinked with 5% divinylbenzene, and H3sal-dahp = dibasic pentadentate ligand derived from salicylaldehyde and 1,3-diamino-2-hydroxypropane) was prepared from the corresponding monomeric oxidovanadium(IV) complex [VIVO(Hsal-dahp)(DMSO)] (1), characterized and successfully used as catalyst for the peroxidase-like oxidation of pyrogallol. The oxidation of pyrogallol to purpurogallin with PS-[VIVO(sal-dahp)] (2) was achieved under mild conditions at pH 7 buffered solution. Plausible intermediate species formed during peroxidase mimicking experiments are proposed, by studying the model complex [VIVO(Hsal-dahp)(DMSO)] (1) by UV-visible and 51V NMR spectroscopies. The high peroxidase mimicking ability of polymer-supported complex 2, its stability in a wide pH range, the easy separation from the reaction media, and the reusability without considerable decrease in activity, suggest that this heterogeneous catalyst has high potential for application in sustainable industrial catalysis.
- Maurya, Mannar R.,Chaudhary, Nikita,Avecilla, Fernando,Correia, Isabel
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- Oxidation of ethanol induced by simple polyphenols: Prooxidant property of polyphenols
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The aerobic oxidation of ethanol to acetaldehyde in water is induced by simple polyphenols, such as pyrogallol or catechol, in the presence of FeSO 4-DTPA (N,N,N′,N′′,N′′- diethylenetriaminepentaacetic acid) catalyst. The amount of acetaldehyde formed becomes an indicator of their "prooxidant" ability in terms of the activation of O2. The "prooxidant" ability of pyrogallol is higher than that of catechol. Electron-withdrawing substituents decrease the ability, whereas electron-donating ones enhance it. The "prooxidant" property is exhibited by the total consequence of two processes: hydroxyl radical (OH) generation from O2 and its capture by phenolic compounds.
- Inui, Takako,Nakahara, Koichi,Uchida, Masaaki,Miki, Wataru,Unoura, Kei,Kokeguchi, Yuki,Hosokawa, Takahiro
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- Peroxidase activity of cationic metalloporphyrin-antibody complexes
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Peroxidase activity of a complex of water-soluble cationic metalloporphyrin with anti-cationic porphyrin antibody is reported. Antibody 12E11G, which was prepared by immunization with a conjugate of 5-(4-carboxyphenyl)-10,15,20- tris(4-methylpyridyl)porphine iodide (3MPy1C), bound to tetramethylpyridylporphyrin iron complex (FeIII-TMPyP) with the dissociation constant of 2.6 × 10-7M. The complex of antibody 12E11G with FeIII-TMPyP catalyzed oxidation of pyrogallol, catechol, and guaiacol. A Lineweaver-Burk plot for the oxidation of pyrogallol catalyzed by the FeIII-TMPyP-antibody complex showed Km = 8.6mM and kcat = 680 min-1. Under the same conditions, K m, and Kcat for horseradish peroxidase (HRP) were 0.8 mM and 1750 min-1, respectively. Although the binding interaction of the antibody to the substrates was one order lower than that of native HRP, the peroxidase activity of this system was in the same order of magnitude as that of HRP.
- Yamaguchi, Hiroyasu,Tsubouchi, Kaori,Kawaguchi, Kazuhide,Horita, Eri,Harada, Akira
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- Biomimetic catalysis of a porous iron-based metal-metalloporphyrin framework
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A porous metal-metalloporphyrin framework, MMPF-6, based upon an iron(III)-metalated porphyrin ligand and a secondary binding unit of a zirconium oxide cluster was constructed; MMPF-6 demonstrated interesting peroxidase activity comparable to that of the heme protein myoglobin as well as exhibited solvent adaptability of retaining the peroxidase activity in an organic solvent.
- Chen, Yao,Hoang, Tran,Ma, Shengqian
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- A graphene oxide/hemoglobin composite hydrogel for enzymatic catalysis in organic solvents
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A graphene oxide/hemoglobin (GO/Hb) composite hydrogel was prepared for catalyzing a peroxidatic reaction in organic solvents with high yields, exceptional activity and stability.
- Huang, Cancan,Bai, Hua,Li, Chun,Shi, Gaoquan
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- Synthesis of reduced graphene oxide-iron nanoparticles with superior enzyme-mimetic activity for biosensing application
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Development of enzyme-mimetic catalysts with sustainability and environmental benignancy has gained considerable attention with the growing demands for large-scale applications in recent years. Here, we demonstrate that the reduced graphene oxide (RGO)-iron nanoparticles (INs) can be utilized as the highly active and cost-effective enzyme-mimetic catalysts for the first time, which have been successfully synthesized by a facile iron-self-catalysis process at room temperature. Benefitting from synergetic effects between RGO and INs, the RGO-INs could efficiently catalyze the oxidization of 3,3′,5,5′-tetramethylbenzidine (TMB) in the presence of H2O2 to produce a typical color reaction, showing the much better peroxidase-like activity than that of each individual part. The mechanistic insight into the enhanced peroxidase-like activity of the RGO-INs was investigated systematically. On the basis of the enzyme-mimetic activity of the RGO-INs, the simple, sensitive, selective and cost-effective colorimetric assays for the detection of hydrogen peroxide and glucose with naked eyes were successfully established. The RGO-INs showed several prominent advantages, such as facile preparation, low cost, tunability in catalytic activity, and low detection limit, over natural peroxidase or other nanomaterial-based alternatives, holding great potential as enzymatic mimics for biosensing applications.
- Li, Lili,Zeng, Chunmei,Ai, Lunhong,Jiang, Jing
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- Dioxidomolybdenum(VI) Complexes of Tripodal Tetradentate Ligands for Catalytic Oxygen Atom Transfer between Benzoin and Dimethyl Sulfoxide and for Oxidation of Pyrogallol
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The reactions of the tripodal tetradentate ONNO donor ligands 6,6′-{[(2-morpholinoethyl)azanediyl]bis(methylene)}bis(2,4-di-tert-butylphenol) (H2L1), 6,6′-{[(2-morpholinoethyl)azanediyl]bis(methylene)}bis(2,4-dimethylphenol) (H2L2) and 6,6′-{[(2-morpholinoethyl)azanediyl]bis(methylene)}bis[2-(tert-butyl)-4-methylphenol] (H2L3) with [MoVIO2(acac)2] (acac = acetylacetonato) in a 1:1 molar ratio in MeOH gave the corresponding cis-dioxidomolybdenum(VI) complexes [MoO2(L1)], [MoO2(L2)] and [MoO2(L3)], respectively, in excellent yields. These complexes were characterized by various spectroscopic (IR, UV/Vis,1H and13C NMR), electrochemical, thermogravimetric, single-crystal XRD, and powder XRD (PXRD) studies. In these complexes, the geometry around the cis-[MoO2]2+core is distorted octahedral, and the ligands are tetradentate and coordinate through two Ophenolate, one Ntripodal, and one Nmorpholineatoms. One of the oxido groups and the morpholine nitrogen atom occupy the axial sites. These complexes were used for catalytic oxygen atom transfer between benzoin and dimethyl sulfoxide (DMSO) in acetonitrile at 80 °C, and the formation of benzil was followed by HPLC. Detailed kinetic studies revealed a first-order rate in benzoin and catalyst, and the rate constant for the second-order oxygen atom transfer reaction was 0.0162 m–1h–1. The formation of the dinuclear intermediates [LMoV–μ-O-MoVL] was established by MALDI-TOF MS and UV/Vis spectroscopy. Its reversible nature was further supplemented by UV/Vis spectroscopy. These complexes also catalyze the oxidation of pyrogallol in a fashion similar to that of transhydroxylases. Under aerobic conditions, the initially formed oxidation product phloroglucinol undergoes further oxidative coupling in the presence of H2O2to give purpurogallin as the final product. This process follows Michaelis–Menten-type kinetics with respect to pyrogallol; the kcatvalues obtained were 394, 300 and 247 h–1for [MoVIO2(L1)], [MoVIO2(L2)] and [MoVIO2(L3)], respectively.
- Maurya, Mannar R.,Uprety, Bhawna,Avecilla, Fernando
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- Surfactant-stabilized small hydrogel particles in oil: Hosts for remarkable activation of enzymes in organic solvents
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Hydrogels of amino acid based cationic surfactant having C16 tails were used to immobilize heme proteins and enzyme. These hydrogelentrapped proteins/enzyme showed remarkable activation when dispersed in organic solvent. The activation effect (ratio of the activity of the hydrogelentrapped enzyme in organic solvent to the activity of the native enzyme in water) of cytochrome c increased up to 350-fold with varying protein and gelator concentration. Hydrogel-entrapped hemoglobin and horseradish peroxidase (HRP) also showed markedly improved activity in organic solvent. Alteration in the structure of the gelator and its supramolecular arrangement showed that the protein immobilized within amphiphilic networks with larger interstitial space exhibited higher activation. This striking activation of hydrogel-entrapped proteins stems from the following effects: 1) the hydrophilic domain of the amphiphilic networks facilitates accessibility of the enzyme to the water-soluble substrate. 2) the surfactant, as an integral part of the amphiphilic network, assists in the formation of a distinct interface through which reactants and products are easily transferred between hydrophilic and hydrophobic domains. 3) Surfactant gelators help in the dispersion and stabilization of gel matrix into small particles in organic solvent, which enhances the overall surface area and results in improved mass transfer. The activation was dramatically improved up to 675-fold in the presence of nongelating anionic surfactants that helped in disintegration of the gel into further smaller-sized particles. Interestingly, hydrogel-immobilized HRP exhibited about 2000-fold higher activity in comparison to the activity of the suspended enzyme in toluene. Structural changes of the entrapped enzyme and the morphology of the matrix were investigated to understand the mechanism of this activation.
- Das, Dibyendu,Roy, Sangita,Debnath, Sisir,Das, Prasanta Kumar
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- Vanadium Complexes Derived from Acetyl Pyrazolone and Hydrazides: Structure, Reactivity, Peroxidase Mimicry and Efficient Catalytic Activity for the Oxidation of 1-Phenylethanol
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Schiff bases obtained from the condensation of acetylpyrazolone (H2ap) with benzoyl hydrazide (bhz), furoyl hydrazide (fah), nicotinoyl hydrazide (nah) and isonicotinoyl hydrazide (inh) [H2ap-bhz (I), H2ap-fah (II) H2ap-nah, (III) and H2ap-inh (IV)], sharing a ONO donor set, upon reaction with [VIVO(acac)2] lead to the formation of [VIVO(ap-bhz)(H2O)] (1), [VIVO(ap-fah)(H2O)] (2), [VIVO(ap-nah)(H2O)] (3) and [VIVO(ap-inh)(H2O)] (4), respectively. These complexes slowly convert to monooxidovanadium(V) complexes [VVO(ap-bhz)(OMe)(MeOH)] (11), [VVO(ap-fah)(OMe)(MeOH)] (12), [VVO(ap-nah)(OMe)(MeOH)] (13) and [VVO(ap-inh)(OMe)(MeOH)] (14) in methanol. The reaction of aqueous K[H2VVO4] with the corresponding potassium salt of the ligands at neutral pH gives dioxidovanadium(V) complexes, K(H2O)[VVO2(ap-bhz)] (5), K(H2O)0.5[VVO2(ap-fah)] (6), [VVO2(Hap-nah)] (9) and [VVO2(Hap-nah)] (10). Acidification of solutions of 5 and 6 affords the neutral complexes [VVO2(Hap-bhz)] (7) and [VVO2(Hap-fah)] (8), respectively. All complexes were characterized by various spectroscopic techniques: FT-IR, UV/Visible, EPR, NMR (1H,13C and51V); elemental analysis, thermal studies, cyclic voltammetry (CV) and single-crystal X-ray analysis. X-ray diffraction studies of complexes 6, 7, 9–12 confirm the ligand's coordination to the metal centre through enolic oxygen (of pyrazolone), azomethine nitrogen and enolic oxygen (hydrazide) atoms. The reactivity of the complexes and their catalytic potential was screened towards their peroxidase mimetic activity in the oxidation of pyragallol in aqueous media with H2O2as oxidant, showing high activity under mild conditions. They were also tested in the catalytic oxidation of 1-phenylethanol with H2O2that yields acetophenone as main product. Parameters such as catalyst and oxidant amount, time, temperature, and solvent effects were optimised for maximum oxidation of 1-phenylethanol. The complexes show excellent catalytic activity towards oxidation of 1-phenylethanol being structural and functional models of the vanadate-dependent haloperoxidases.
- Maurya, Mannar R.,Sarkar, Bithika,Avecilla, Fernando,Correia, Isabel
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- Bioinorganic Nanocomposite Hydrogels Formed by HRP-GOx-Cascade-Catalyzed Polymerization and Exfoliation of the Layered Composites
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The mild preparation of multifunctional nanocomposite hydrogels is of great importance for practical applications. We report that bioinorganic nanocomposite hydrogels, with calcium niobate nanosheets as cross-linkers, can be prepared by dual-enzyme-triggered polymerization and exfoliation of the layered composite. The layered HRP/calcium niobate composites (HRP=horseradish peroxidase) are formed by the assembly of the calcium niobate nanosheets with HRP. The dual-enzyme-triggered polymerization can induce the subsequent exfoliation of the layered composite and final gelation through the interaction between polymer chains and inorganic nanosheets. The self-immobilized HRP-GOx enzymes (GOx=glucose oxidase) within the nanocomposite hydrogel retain most of enzymatic activity. Evidently, their thermal stability and reusability can be improved. Notably, our strategy could be easily extended to other inorganic layered materials for the fabrication of other functional nanocomposite hydrogels.
- Liao, Chuan-An,Wu, Qing,Wei, Qing-Cong,Wang, Qi-Gang
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- High catalytic activities of artificial peroxidases based on supramolecular hydrogels that contain heme models
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Composed of a supramolecular hydrogel and a heme model compound, a new type of artificial peroxidase shows high catalytic activity in organic media. The activity of this new type of artificial enzyme is significantly higher than that of the heme model compounds alone. Changes in the distal substituents above the coordinated-metal centers of the model compounds directly modulate catalytic activity. This supramolecular-hydrogelbased artificial enzyme is most active in toluene, reaching about 90% of the nascent activity of horseradish peroxidase. Moreover, this study confirms that the incorporation of the heme models into the nanofibers of gelators accounts for most of the enhancement of catalytic activity.
- Wang, Qigang,Yang, Zhimou,Ma, Manlung,Chang, Chi K.,Xu, Bing
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- Oxidation of phenyl compounds using strongly stable immobilized-stabilized laccase from Trametes versicolor
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The hydrolysis of phenolic compounds using an immobilized and highly active and stable derivative of laccase from Trametes versicolor is presented. The enzyme was immobilized on aldehyde supports. For this, the enzyme was enriched in amino groups by chemical modification of its carboxyl groups. The aminated enzyme was immobilized with a high recovered activity (over 60%). Aldehyde derivatives were more stable than soluble or aminated-soluble enzyme and the reference derivatives after incubation in different inactivating conditions (high temperatures, different pH values or presence of organic cosolvents). The most stable derivative was obtained immobilizing the chemically aminated enzyme at pH 10 on aldehyde supports with a stabilization factor approximately 280 fold after incubation at pH 7 and 55 C. In addition, it was possible to prepare immobilized derivatives with a maximal enzyme loading of 60 mg g-1 of support. This derivative could be reused for 10 reaction cycles with negligible lost of activity.
- Addorisio, Veria,Sannino, Filomena,Mateo, Cesar,Guisan, Jose M.
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- Influence of pristine SWNTs in supramolecular hydrogelation: Scaffold for superior peroxidase activity of cytochrome c
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The influence of pristine SWNTs in supramolecular hydrogelation of amphiphilic dipeptide carboxylates is delineated. The developed SWNT-nanohybrids with notable mechanical strength act as a scaffold for superior peroxidase activity of cytochrome c in organic media.
- Kar, Tanmoy,Mandal, Subhra Kanti,Das, Prasanta Kumar
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- A polymer grafted oxidomethoxidovanadium(V) complex of an ONO donor ligand mimicking peroxidase activity
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The reaction between [VIVO(acac)2] and the ONO donor tridentate ligand H2hap-iah (I) [H2hap-iah = Schiff base obtained by the condensation of equimolar amounts of o-hydroxyacetophenone (hap) and indole-3-acetic hydrazide (iah)] in an equimolar ratio under an oxygen atmosphere in refluxing methanol gives [VVO(OMe)(hap-iah)] (1). Treatment of 1 in methanol with H2O2 in the presence of KOH results in the formation of K[VVO(O2)(hap-iah)] (2). Complex 1 has been grafted into chloromethylated polystyrene cross-linked with 5% divinylbenzene {now abbreviated as PS-[VVO(OMe)(hap-iah)] (3)} via covalent bonding through the imino nitrogen atom of the indole group. The two complexes have been characterized by various spectroscopic techniques (IR, electronic, 1H, 13C and 51V NMR, ESI-MS), analytical and thermal studies. The polymer-grafted complex 3 has also been analyzed by field-emission scanning electron micrographs (FE-SEM) as well as energy dispersive X-ray (EDAX) studies. The polymer-grafted complex 3 has been used as a catalyst for the peroxidase-like oxidation of pyrogallol to purpurogallin in pH 7 buffer solution. Its high peroxidase mimicking ability, easy separation from the reaction medium and the reusability, without any considerable decrease in activity, suggest the practical utility of the catalyst.
- Maurya, Mannar R.,Kumar, Naveen,Chaudhary, Nikita
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- Heterogeneous Manganese-Catalyzed Oxidase C?H/C?O Cyclization to Access Pharmaceutically Active Compounds
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Heterogeneous manganese-catalyzed C?H oxidative couplings were accomplished to gain access to pharmaceutically relevant 2-aminophenoxazin-3-ones and to diaminophenazine and purpurogallin moieties in excellent yields. The user-friendly K-OMS-2 oxidase strategy proved to be more versatile and robust than enzymatic catalysts-based procedures allowing a wider substrate scope and being effectively reusable as proven by leaching measurements and XRD analyses.
- Ferlin, Francesco,Marini, Alberto,Ascani, Nicola,Ackermann, Lutz,Lanari, Daniela,Vaccaro, Luigi
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p. 449 - 454
(2019/12/12)
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- Unraveling the anti-influenza effect of flavonoids: Experimental validation of luteolin and its congeners as potent influenza endonuclease inhibitors
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The biological effects of flavonoids on mammal cells are diverse, ranging from scavenging free radicals and anti-cancer activity to anti-influenza activity. Despite appreciable effort to understand the anti-influenza activity of flavonoids, there is no clear consensus about their precise mode-of-action at a cellular level. Here, we report the development and validation of a screening assay based on AlphaScreen technology and illustrate its application for determination of the inhibitory potency of a large set of polyols against PA N-terminal domain (PA-Nter) of influenza RNA-dependent RNA polymerase featuring endonuclease activity. The most potent inhibitors we identified were luteolin with an IC50 of 72 ± 2 nM and its 8-C-glucoside orientin with an IC50 of 43 ± 2 nM. Submicromolar inhibitors were also evaluated by an in vitro endonuclease activity assay using single-stranded DNA, and the results were in full agreement with data from the competitive AlphaScreen assay. Using X-ray crystallography, we analyzed structures of the PA-Nter in complex with luteolin at 2.0 ? resolution and quambalarine B at 2.5 ? resolution, which clearly revealed the binding pose of these polyols coordinated to two manganese ions in the endonuclease active site. Using two distinct assays along with the structural work, we have presumably identified and characterized the molecular mode-of-action of flavonoids in influenza-infected cells.
- Albi?ana, Carlos Berenguer,Brynda, Ji?í,Fanfrlík, Jind?ich,Flieger, Miroslav,Hodek, Jan,Karlukova, Elena,Ko?í?ek, Milan,Konvalinka, Jan,Machara, Ale?,Majer, Pavel,Radilová, Kate?ina,Weber, Jan,Zima, Václav
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supporting information
(2020/09/09)
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- Activity adaptability of a DhHP-6 peroxidase-mimic in wide pH and temperature ranges and solvent media
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Separating the active units while maintaining the majority of the functions of enzymes seems to be a paradox and therefore challenging, not to mention also improving the adaptability to harsh conditions simultaneously. In this paper, we demonstrate that a well-designed hexapeptide molecule, deuterohemin-β-Ala-His-Thr-Val-Glu-Lys (DhHP-6), adapted from cytochrome c, shows superior peroxidase activity over a wide pH and temperature range. The activity of DhHP-6 was first assessed via three substrates (i.e., 2,2′azinodi(3-ethylbenzthiazoline)-6-sulfonate (ABTS), 1,2,3-trihydroxybenzene (THB) and phenol) with reference to the classically studied examples microperoxidase (MP-11) and horseradish peroxidase (HRP). The environmental adaptability was assessed via three factors: pH, temperature, and the polarity of solvents. In the phenol substrate model reaction, DhHP-6 shows superior specific activity (749.73 U mg-1) and adaptability compared to HRP (311.32 U mg-1). Under the optimum solvent conditions (15% methanol by volume ratio), the enzymatic efficiency (Vm/Km) of DhHP-6 reached 27.9 × 10-3 s-1, 16-times higher than that of HRP (1.81 × 10-3 s-1). The methanol concentration dependent electron paramagnetic spectra show an axial-promoted intermediate process for the phenol catalytic reaction. This work provides a protocol and feasible methodology for the design and fabrication of natural enzyme mimicking small molecules that maintain most of their native activity for better biocatalytic applications in organic pollutant remediation and other related processes.
- Huang, Xuri,Li, Zhengqiang,Liu, Min,Ma, Li,Sun, Xiaoli,Wang, Zhi,Yan, Jiaqing,Yuan, Long,Zhao, Zijian
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p. 1848 - 1857
(2020/04/09)
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- Anti-melanogenic cosmetic composition of Purpurogallin as an efficient component and preparation method of the same
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The present invention relates to an anti-melanogenic functional cosmetic composition comprising purpurogallin, which is an oxidation product of pyrogallol, as an effective component, using pear-derived polyphenol oxidative enzyme. The present invention has an excellent effect of providing an anti-melanogenic functional cosmetic composition for reducing biosynthesis activities of melanin by inhibiting activities of MITF controlling expression of genes associated with formation of melanin.COPYRIGHT KIPO 2017
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Paragraph 0016-0017
(2017/12/17)
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- 3D-Printing inside the Glovebox: A Versatile Tool for Inert-Gas Chemistry Combined with Spectroscopy
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3D-Printing with the well-established 'Fused Deposition Modeling' technology was used to print totally gas-tight reaction vessels, combined with printed cuvettes, inside the inert-gas atmosphere of a glovebox. During pauses of the print, the reaction flasks out of acrylonitrile butadiene styrene were filled with various reactants. After the basic test reactions to proof the oxygen tightness and investigations of the influence of printing within an inert-gas atmosphere, scope and limitations of the method are presented by syntheses of new compounds with highly reactive reagents, such as trimethylaluminium, and reaction monitoring via UV/VIS, IR, and NMR spectroscopy. The applicable temperature range, the choice of solvents, the reaction times, and the analytical methods have been investigated in detail. A set of reaction flasks is presented, which allow routine inert-gas syntheses and combined spectroscopy without modifications of the glovebox, the 3D-printer, or the spectrometers. Overall, this demonstrates the potential of 3D-printed reaction cuvettes to become a complementary standard method in inert-gas chemistry.
- Lederle, Felix,Kaldun, Christian,Namyslo, Jan C.,Hübner, Eike G.
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p. 255 - 266
(2016/05/19)
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- Bioactive MIL-88A Framework Hollow Spheres via Interfacial Reaction In-Droplet Microfluidics for Enzyme and Nanoparticle Encapsulation
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Functional bio-MOF hollow spheres with controlled size in the 35-2000 μm range were successfully synthesized by interfacial reaction using a continuous-flow droplet microfluidic system in a single step and one-flow strategy. The architecture of MIL-88A frameworks was extended from single-shell to double-shell hollow spheres. Moreover, various functional nanoparticles (silica, cobalt, and UiO-66(Zr) MOF) were directly encapsulated in the single-shell hollow spheres, while maintaining the functionality of the cargo. In particular, three kinds of enzymes (glycerol dehydrogenase, horseradish peroxidase, and acetylcholinesterase) were also encapsulated inside the single-shell hollow spheres under mild conditions. The catalytic activity and the superior recyclability of the encapsulated enzymes were demonstrated against free enzymes.
- Jeong, Guan-Young,Ricco, Raffaele,Liang, Kang,Ludwig, Johanna,Kim, Jin-Oh,Falcaro, Paolo,Kim, Dong-Pyo
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p. 7903 - 7909
(2015/12/20)
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- ANTAGONISTS OF THE TOLL-LIKE RECEPTOR 1/2 COMPLEX
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Provided are compounds, compositions and methods for treating Toll-like receptor 1/2 complex (TLRI/2) related inflammatory disorders. Small molecules, based on the benzotropolone scaffold, capable of influencing downstream signaling are dislcosed as well as methods of making and modifying these molecules. Also provided are methods for treating a subject for a clinical condition associated with Toll? like receptor complex 1/2 activation, comprising administering to the subject an effective amount of a benzotropolone compound.
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Page/Page column 18; 19; 20
(2014/02/16)
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- ANTI-OBESITY AGENT COMPRISING COMPOUND CONTAINING BENZOTROPOLONE RING
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The object of the present invention is to provide an anti-obesity agent which contains a tea-derived component and which is safe and does not compromise the flavor of foods and beverages. According to the present invention, a safe and palatable anti-obesity agent can be provided by incorporating a benzotropolone ring-containing compound which has tea-derived, high inhibitory activities against lipase and alfa-glucosidase. The anti-obesity agent of the present invention does not compromise the flavor of foods and beverage, has palatability, and can be used in various use applications including foods and beverages intended for health enhancement such as reduction in triglycerides.
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Page/Page column 11
(2012/03/27)
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- Zirconium-metalloporphyrin PCN-222: Mesoporous metal-organic frameworks with ultrahigh stability as biomimetic catalysts
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Biomimetic MOF: Extremely stable MOFs with different open metal sites and ultra-large 1D channels, PCN-222 (Fe, Mn, Co, Ni, Cu, and Zn), have been assembled with eight-connected Zr6 clusters and redox-active metalloporphyrin motifs. PCN-222(Fe) shows peroxidase-like activity in aqueous solution, exhibiting highly effective biomimetic oxidation on a number of substrates. Copyright
- Feng, Dawei,Gu, Zhi-Yuan,Li, Jian-Rong,Jiang, Hai-Long,Wei, Zhangwen,Zhou, Hong-Cai
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supporting information
p. 10307 - 10310,4
(2012/12/12)
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- Zirconium-metalloporphyrin PCN-222: Mesoporous metal-organic frameworks with ultrahigh stability as biomimetic catalysts
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Biomimetic MOF: Extremely stable MOFs with different open metal sites and ultra-large 1D channels, PCN-222 (Fe, Mn, Co, Ni, Cu, and Zn), have been assembled with eight-connected Zr6 clusters and redox-active metalloporphyrin motifs. PCN-222(Fe) shows peroxidase-like activity in aqueous solution, exhibiting highly effective biomimetic oxidation on a number of substrates. Copyright
- Feng, Dawei,Gu, Zhi-Yuan,Li, Jian-Rong,Jiang, Hai-Long,Wei, Zhangwen,Zhou, Hong-Cai
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supporting information
p. 10307 - 10310
(2013/01/15)
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- Striking improvement in peroxidase activity of cytochrome c by modulating hydrophobicity of surface-functionalized gold nanoparticles within cationic reverse micelles
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This work demonstrates a remarkable enhancement in the peroxidase activity of mitochondrial membrane protein cytochrome c (cyt c) by perturbing its tertiary structure in the presence of surface-functionalised gold nanoparticles (GNPs) within cetyltrimethylammonium bromide (CTAB) reverse micelles. The loss in the tertiary structure of cyt c exposes its heme moiety (which is buried inside in the native globular form), which provides greater substrate (pyrogallol and H2O2) accessibility to the reactive heme residue. The surfactant shell of the CTAB reverse micelle in the presence of co-surfactant (n-hexanol) exerted higher crowding effects on the interfacially bound cyt c than similar anionic systems. The congested interface led to protein unfolding, which resulted in a 56-fold higher peroxidase activity of cyt c than that in water. Further perturbation in the protein's structure was achieved by doping amphiphile-capped GNPs with varying hydrophobicities in the water pool of the reverse micelles. The hydrophobic moiety on the surface of the GNPs was directed towards the interfacial region, which induced major steric strain at the interface. Consequently, interaction of the protein with the hydrophobic domain of the amphiphile further disrupted its tertiary structure, which led to better opening up of the heme residue and, thereby, superior activity of the cyt c. The cyt c activity in the reverse micelles proportionately enhanced with an increase in the hydrophobicity of the GNP-capping amphiphiles. A rigid cholesterol moiety as the hydrophobic end group of the GNP strikingly improved the cyt c activity by up to 200-fold relative to that found in aqueous buffer. Fluorescence studies with both a tryptophan residue (Trp59) of the native protein and the sodium salt of fluorescein delineated the crucial role of the hydrophobicity of the GNP-capping amphiphiles in improving the peroxidase activity of cyt c by unfolding its tertiary structure within the reverse micelles.
- Maiti, Subhabrata,Das, Krishnendu,Dutta, Sounak,Das, Prasanta Kumar
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supporting information
p. 15021 - 15030
(2013/01/15)
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- Enzymatic activity and thermal stability of metallo proteins in hydrated ionic liquids
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Hydrated choline dihydrogen phosphate (Hy[ch][dhp]) containing 30 wt% water was investigated as a novel protein solvent. The Hy[ch][dhp] dissolved some metallo proteins (cytochrome c, peroxidase, ascorbate oxidase, azurin, pseudoazurin and fructose dehydrogenase) without any modification. These proteins retained the surroundings of the active site after dissolution in Hy[ch][dhp]. Some metallo proteins were found to retain their activity in the Hy[ch][dhp].
- Fujita, Kyoko,Ohno, Hiroyuki
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experimental part
p. 1093 - 1099
(2011/12/16)
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- Biocatalytic oxidation by chloroperoxidase from Caldariomyces fumago in polymersome nanoreactors
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The encapsulation of chloroperoxidase from Caldariomyces fumago (CPO) in block copolymer polymersomes is reported. Fluorescence and electron microscopy show that when the encapsulating conditions favour self-assembly of the block copolymer, the enzyme is incorporated with concentrations that are 50 times higher than the enzyme concentration before encapsulation. The oxidation of two substrates by the encapsulated enzyme was studied: i) pyrogallol, a common substrate used to assay CPO enzymatic activity and ii) thioanisole, of which the product, (R)-methyl phenyl sulfoxide, is an important pharmaceutical intermediate. The CPO-loaded polymersomes showed distinct reactivity towards these substrates. While the oxidation of pyrogallol was limited by diffusion of the substrate into the polymersome, the rate-limiting step for the oxidation of thioansiole was the turnover by the enzyme.
- De Hoog,Nallani,Cornelissen,Rowan,Nolte,Arends
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experimental part
p. 4604 - 4610
(2009/12/08)
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- Molecular hydrogel-immobilized enzymes exhibit superactivity and high stability in organic solvents
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This communication describes the use of a molecular hydrogel to immobilize enzymes for catalyzing reactions in an organic solvent to attain superactivity and exceptional stability. The Royal Society of Chemistry.
- Wang, Qigang,Yang, Zhimou,Wang, Ling,Ma, Manlung,Xu, Bing
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p. 1032 - 1034
(2008/01/01)
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- A supramolecular-hydrogel-encapsulated hemin as an artificial enzyme to mimic peroxidase
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(Figure Presented) Faking it: The use of a supramolecular hydrogel as the structural component of artificial enzymes provides a new and useful approach to the development of biomimetic catalysts. In toluene, hemin chloride encapsulated in such a hydrogel achieves about 60% nascent catalytic activity of horseradish peroxidase. Additionally, the activity of hemin in the hydrogel is 387.1 times greater than that of free hemin.
- Wang, Qigang,Yang, Zhimou,Zhang, Xieqiu,Xiao, Xudong,Chang, Chi K.,Xu, Bing
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p. 4285 - 4289
(2008/03/12)
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- Benzotropolone derivatives and modulation of inflammatory response
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The present invention provides novel benzotropolone derivatives represented by the general formula: 1 including neotheaflavate B and EGCGCa. The benzotropolone derivatives of the present invention are effective antioxidant and anti-inflammatory agents. The present invention also provides novel method of synthesizing benzotropolone compounds in high yields and method of treating inflammatory conditions using benzotropolone containing compounds.
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Page/Page column 11
(2008/06/13)
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- Enzymatic synthesis of tea theaflavin derivatives and their anti-inflammatory and cytotoxic activities
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Derivatives based on a benzotropolone skeleton (9-26) have been prepared by the enzymatic coupling (horseradish peroxidase/H2O2) of selected pairs of compounds (1-8), one with a vic-trihydroxyphenyl moiety, and the other with an ortho-dihydroxyphenyl structure. Some of these compounds have been found to inhibit TPA-induced mice ear edema, nitric oxide (NO) synthesis, and arachidonic acid release by LPS-stimulated RAW 264.7 cells. Their cytotoxic activites against KYSE 150 and 510 human esophageal squamous cell carcinoma and HT 29 human colon cancer cells were also evaluated.
- Sang, Shengmin,Lambert, Joshua D.,Tian, Shiying,Hong, Jungil,Hou, Zhe,Ryu, Jae-He,Stark, Ruth E.,Rosen, Robert T.,Huang, Mou-Tuan,Yang, Chung S.,Ho, Chi-Tang
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p. 459 - 467
(2007/10/03)
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- PHOTOCHIMIE ET ENVIRONMENT II. PHOTOCHIMIE DES TRIPHENOLS EN SOLUTION AQUEUSE DILUEE
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In aqueous solution the formation of phenoxy radicals from elecronically excited triphenols occurs through a primary photochemical process assisted by oxygen.Products observed in the photooxidation of triphenols are accounted by secondary reactions of these radicals.The nature of the major secondary processes depends on the triphenol under investigation.The phenoxy radicals formed from 1,2,4-trihydroxybenzene are poorly reactive with oxygen and disappear through a disproportionation.A fairly unstable hydroxybenzoquinone is formed.The corresponding phenoxy radicals of 1,2,3-trihydroxybenzene lead to purpurogallin and are oxidized into dihydroxybenzoquinone.The material balance in the photooxidation of the 1,3,5-trihydroxybenzene is poor; the radicals formed are readily oxidized and unstable oxidation products are formed.No accumulation of the primary photoproducts is observed in a long term photooxidation of triphenols.
- Perbet, Gilles,Boule, Pierre,Lemaire, Jacques
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