BIOTECHNOLOGY LETTERS
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2016
·Vol. 38
·期 7
·1121-1129
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IF 1.639
Zhou Jian Qin,He Ting,Wang Jian Wen
Objectives To establish a method for microbial trans glutaminase (mTG)-mediated PEGylation of proteins at the level of lysine (Lys) residues. Results Carboxybenzyl-glutaminyl–glycinyl-methoxypolyethylene glycol (CBZ-QG-mPEG) was prepared by introducing carboxybenzyl-glutaminyl-glycine (CBZ-QG) to mPEG amine. The analysis by Fourier transform infrared spectroscopy and SDS-PAGE showed that CBZ-QG-mPEG was successfully synthesized and can be recognized by mTG as an acyl donor to modify therapeutic protein, cytochrome c (cyt c ). Finally, under an optimized condition (cyt c 0.5 mg/ml, CBZ-QG-mPEG 11.25 mg/ml, mTG 0.5 mg/ml, 37 °C, 2 h), the PEGylation yield reached 76.5 %. Conclusions This is the first study regarding the PEGylation of protein at the level of Lys residues catalyzed by mTG. The novel method could be employed to immobilize active proteins and modify therapeutic proteins.
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Frontiers in Pharmacology
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2017
·
IF 4.4
Liu Qing,Xiao Xu-Hui,Hu Liu-Bing,Jie Hui-Yang,Wang Ying,Ye Wen-Cai,Li Man-Mei,Liu Zhong
Anemone flaccida Fr. Schmidt (Ranunculaceae) (Di Wu in Chinese) is used to treat punch injuries and rheumatoid arthritis (RA). Our previous report has shown that crude triterpenoid saponins from Anemone flaccida exhibited anti-arthritic effects on type II collagen-induced arthritis in rats. Furthermore, anhuienoside C (AC), a saponin compound isolated from A. flaccida, was observed to suppress the nitric oxide production in lipopolysaccharide (LPS)-treated macrophage RAW 264.7 cells. In this study, we examined the effects of AC on the prevention and treatment of collagen-induced arthritis in a mouse model and evaluated the potential mechanisms involved. We observed that oral administration of AC significantly suppressed the paw swelling and arthritic score, decreased the body weight loss, and decreased the spleen index. Improvement in the disease severity was accompanied by the reduction of cluster of differentiation 68 (CD68)-positive cells in the ankle joint and inhibition of the pro-inflammatory cytokine tumor necrosis factor alpha (TNF-α) in the synovium of the joint. Mechanistic studies indicated that AC exerted its anti-inflammatory activity by inhibiting the mRNA expression levels of inducible nitric oxide synthase, cyclooxygenase-2, TNF-α, interleukin (IL)-1β, and IL-6 and by suppressing the production of inflammatory cytokines such as TNF-α, IL-1β, and IL-6 in LPS-treated RAW 264.7 cells. AC also blocked the LPS-induced activation of the extracellular signal-regulated kinase, c-Jun N-terminal kinase, and p38 mitogen-activated protein kinase pathways. Additionally, the LPS-induced activation of nuclear factor kappa-B (NF-κB) was significantly suppressed by AC treatment, as indicated by down-regulation of TLR4 and inhibition of the nuclear translocation of NF-κB p65 and by activation and degradation of the inhibitor of kappa B. These findings indicated that AC has a great potential to be developed as a therapeutic agent for human RA.
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Journal of CO2 Utilization
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2016
·
IF 4.764
Xiying Fu,Dagang Zhou,Kai Wang,Huanwang Jing
Pd/C was found to be an excellent catalyst in the coupling reaction of carbon dioxide and epoxides with tetrabutylammonium iodide (TBAI) as cocatalyst and the corresponding cyclic carbonates were obtained in good yields and high selectivities. 3-Chloropropylene carbonate was synthesized under extremely mild conditions of room temperature and atmosphere. The proposed mechanism was also calculated and confirmed by DFT. The palladium catalyst could be simply recycled and reused for 5 times without significant loss of activity.
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CHEMICAL ENGINEERING JOURNAL
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2016
·
IF 5.31
Nailing Gao,Ziyang Lu,Xiaoxu Zhao,Zhi Zhu,Youshan Wang,Dandan Wang,Zhoufa Hua,Chunxiang Li,Pengwei Huo,Minshan Song
In order to realize the rational utilization of waste, C/Fe 3 O 4 was obtained by using biomass as the carbon source and prepared via one-step method, afterwards, a double conductive C/Fe 3 O 4 /Bi 2 O 3 composite photocatalyst was further synthesized via solvothermal method. Due to the good double conductivity, the electrons in Bi 2 O 3 could be transported to C/Fe 3 O 4 , which greatly inhibited the recombination of electron-hole pairs, it is worth noting that the double conductivity effectively blocked the reverse transfer of electrons to Bi 2 O 3 . Consequently, the photodegradation rate of C/Fe 3 O 4 /Bi 2 O 3 composite photocatalyst reached 91%, which was much higher than that of pure Bi 2 O 3 . In addition, the mechanism exploration experiment showed that h + was the main activity specie, meanwhile, the photocatalytic electron transfer mechanism was also investigated.
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ChemSusChem
·
2016
·Vol. 9
·期 22
·3220-3229
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IF 7.116
Haiwei Guo,Bo Zhang,Changzhi Li,Chang Peng,Tao Dai,Haibo Xie,Aiqin Wang,Tao Zhang
Graphical Breaking up : Tungsten carbide shows remarkable activity in selective C−O bond cleavage of typical β-O-4 model compounds and deconstruction of lignin feedstocks. High yields of C−O cleavage products from model compounds (up to 96.8 %) and from lignin feedstock (up to 70.7 %) are obtained without destroying the aromatic rings. A remarkably effective method for the chemoselective cleavage of the C−O bonds of typical β-O-4 model compounds and the deconstruction of lignin feedstock was developed by using tungsten carbide as the catalyst. High yields of C−O cleavage products (up to 96.8 %) from model compounds and liquid oils (up to 70.7 %) from lignin feedstock were obtained under low hydrogen pressure (0.69 MPa) in methanol. The conversion efficiency was determined to a large extent by solvent effects and was also affected by both the electronic and steric effects of the lignin model compounds. In situ W 2 C/activated carbon (AC)-catalyzed hydrogen transfer from methanol to the substrate was proposed to be responsible for the high performance in methanol solvent. The conversion of 2-(2-methoxyphenoxy)-1-phenylethanol showed that the catalyst could be reused five times without a significant loss in activity for C−O bond cleavage, whereas the selectivity to value-added styrene increased markedly owing to partial oxidation of the W 2 C phase according to X-ray diffraction, Raman spectroscopy, and transmission electron microscopy characterization. 2 D-HSQC-NMR spectroscopy analysis showed that W 2 C/AC exhibited high activity not only for β-O-4 cleavage but also for the deconstruction of more resistant α-O-4 and β-β linkages, so that a high yield of liquid oil was obtained from lignin. Corn stalk lignin was more liable to be depolymerized than birch lignin owing to its loosened structure (scanning electron microscopy results), larger surface area (BET results), and lower molecular weight (gel-permeation chromatography results), whereas its liquid oil composition was more complicated than that of birch wood lignin in that the former lignin contained more p -hydroxyphenyl units and the former contained noncanonical units.
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RSC Advances
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2016
·Vol. 6
·期 102
·100427-100436
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IF 3.289
Binbin Ding,Yuming Zhou,Man He,Tingyuan Huang,Shiwei Li,Shuang Huang,Wenlu Pan
We report uniform hollow CeO2/Au/C nanocatalysts with hierarchical structures fabricated successfully via an etching process. The whole preparation method involves the synthesis of SiO2 spheres, a sequential deposition of CeO2, Au NPs of 2–5 nm and then C layers through hydrothermal processes, crystallization of C by calcination and finally etching of the inner silica spheres to construct the hollow structures. The as-obtained nanostructures are characterized by transmission electron microscope (TEM), scanning electron microscope (SEM), X-ray diffraction (XRD), UV-Vis spectroscopy and energy dispersion X-ray spectroscopy (EDX). The CeO2/Au/C composite shows a multilayer structure including the hollow ceria spheres and the C layers, where Au NPs are located between the two layers. In this work, the reduction of 4-NP is employed as a model reaction to test the catalytic performance. The results indicate that the hollow CeO2/Au/C nanospheres exhibit a higher catalytic performance, comparing with the hollow CeO2/Au and Au/C nanospheres. The presences of the C shells and CeO2 layers can improve the catalytic activity. In addition, the hollow CeO2/Au/C structures can be easily recycled without an obvious decrease of the catalytic activities in the reaction.
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CERAMICS INTERNATIONAL
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2016
·
IF 2.758
Chunlong Dai,Minqiang Wang,Jingang Yang,Linyu Hu,Maowen Xu
A novel MnO@Amorphous C-Carbon nanotubes (MnO@C-CNTs) composite is prepared by chemical vapor deposition (CVD). When used as an anode material for Li-ion batteries, the MnO@C-CNTs composite exhibits an initial discharge capacity of 1164 mA h g −1 at 100 mA g −1 and the discharge capacity gradually increased from 571.7 mA h g −1 to 654 mA h g −1 after 100 cycles at 1 A g −1 , which shows an increase of the capacity rather than attenuation. Furthermore, the MnO@C-CNTs electrode can deliver a capacity of up to 228 mA h g −1 at 5 A g −1 . These results indicate that the three-dimensional conductive network of the MnO@C-CNTs composite could prevent the aggregation of MnO particles, and its open structure allows electrolyte penetration, and reduces the diffusion path of the lithium ions , hence maximizes utilization of the electrochemically active MnO particles, while enhances the conductivity of electrode material and Li + transport. This work offers a universal approach to design various metal oxides@C-CNTs composite.
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JOURNAL OF APPLIED ELECTROCHEMISTRY
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2016
·Vol. 46
·期 11
·1147-1155
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IF 2.223
Jin Biyao,Zhang Yanyu,Zhao Lianhua
Abstract PdAu 3:1/C-1 and PdAu 3:1/C-2 nanoparticles were prepared in methylene chloride and water, respectively. The syntheses featured the use of tetrabutylammonium hydroxide as a phase-transfer agent and stabilizer. Electrochemical characterization showed that compared with PdAu 3:1/C-2, PdAu 3:1/C-1 had superior ethanol oxidation reaction (EOR) activity in alkaline media. The results of X-ray powder diffraction indicated that PdAu 3:1/C-1 was an alloy, whereas PdAu 3:1/C-2 was a heterogeneous mixture of the two metals. Moreover, transmission electron microscope analyses revealed that the PdAu 3:1/C-1 nanoparticles dispersed homogeneously on the carbon carrier without evident aggregation. Further, the X-ray photoelectron spectroscopy results demonstrated that the hydroxyl content was higher on the surface of PdAu 3:1/C-1 than that of PdAu 3:1/C-2. The increase of adsorptive hydroxyl on the surface of PdAu 3:1/C-1 could facilitate the adsorption and oxidation of CO on the catalyst surface, thus improving EOR activity and catalyst stability. Graphical Abstract
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THIN SOLID FILMS
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2017
·
IF 1.879
Xueyao Xie,Xin Yin,Lixin Song,Pingfan Du,Ni Li,Lin Qi,Jie Xiong
The flexible Al 2 O 3 /carbon composite nanofibers (ACNFs) film was synthesized by electrospinning. And the effects of carbonization temperature on the structures and properties of ACNFs were investigated. All the obtained ACNFs had rough surface and random orientations, and the alumina nanostructures were closely jointed to the carbon nanofibers . Besides, the crystallinity of alumina and carbon increased with carbonization temperature. As a result, the flexural property of ACNFs film decreased, and the electrical property greatly increased with the increase of carbonization temperature. When the carbonization temperature was 900 °C, the flexible ACNFs composite film was used as a counter electrode for flexible dye-sensitized solar cells. A power conversion efficiency of 2.84% was achieved. If the catalyst activity of the film was further improved, the conversion efficiency may be further improved.
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BIORESOURCE TECHNOLOGY
·
2014
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IF 5.039
Riyang Shu,Jinxing Long,Zhengqiu Yuan,Qi Zhang,Tiejun Wang,Chenguang Wang,Longlong Ma
An efficient lignin depolymerization process with highly controllable product distribution was presented using metal chloride (MCl x ) cooperated with Pd/C. The catalytic performances of MCl x were investigated. The effect of reaction conditions on the lignin depolymerization and products distribution were also studied. Results showed that more than 35.4% yield of phenolic monomer including 7.8% phenols and 1.1% guaiacols could be obtained under optimized condition. And the product distribution can be efficiently controlled by the modification of the metal cation through different pathway of Lewis acid catalysis and coordination catalysis. Furthermore, the Pd/C catalyst showed an excellent recyclability, where no significant loss of the catalytic activity was exhibited after 3 runs. Moreover, the product control mechanism was proposed.
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RSC Advances
·
2015
·Vol. 5
·期 91
·74774-74782
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IF 3.84
Wenjun Zhu,Hui Yang,Wenkui Zhang,Hui Huang,Xinyong Tao,Yang Xia,Yongping Gan,Xingzhong Guo
A Li4Ti5O12/TiO2/carbon (Li4Ti5O12/TiO2/C) nanocrystalline composite has been successfully synthesized by a facile sol–gel method and subsequent calcination treatment. Moreover, pure Li4Ti5O12, Li4Ti5O12/C and Li4Ti5O12/TiO2 composites have also been synthesized for comparison. All the samples present a nanocrystalline structure with a uniform size distribution, and abundant phase interfaces can be detected for the Li4Ti5O12/TiO2 and Li4Ti5O12/TiO2/C composites. Electrochemical measurements demonstrate that the resultant Li4Ti5O12/TiO2/C composite exhibits a superior rate capability and cycle stability in comparison with pure Li4Ti5O12, Li4Ti5O12/C and Li4Ti5O12/TiO2 composites, which can be attributed to a high grain boundary density, abundant phase interfaces and in situ formed carbon, for storing extra lithium ions, enhancing rapid lithium insertion/extraction kinetics and improving the electron transport rate.
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SPECTROSCOPY LETTERS
·
2013
·
IF 0.667
Yun-Chang Fan,Xue-Yun Gong,Jing Li,Lei Zhang,Chun-Jia Sun
The interaction of an amino-functionalized ionic liquid, 1-(2-aminoethyl)-3-butylimidazolium bromide ([NH2C2C4im]Br), with cytochrome c (cyt c) at pH 7.4 was investigated using fluorescence and UV-Vis absorption spectroscopic techniques. From the experimental results, it is found that cyt c has a strong ability to quench the intrinsic fluorescence of [NH2C2C4im]Br and the quenching mechanism is considered as a static quenching process. The binding constants and the number of binding sites (n) were calculated at different temperatures. The thermodynamic parameters such as free energy change (ΔG), enthalpy change (ΔH), and entropy change (ΔS) were calculated by thermodynamic equations. According to the results, the values of ΔG, ΔH, and ΔS are all negative, suggesting that interaction between [NH2C2C4im]Br and cyt c is spontaneous and mainly driven by hydrogen bonding and van der Waals forces.
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