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61.
Solid state bio-processing of wheat straw was carried out through an indigenous fungal strain Pleurotus ostreatus IBL-02 under pre-optimized fermentation conditions. The maximum activity, 692±12 U/mL, of the industrially important manganese peroxidase (MnP) enzyme was recorded after five days of still culture incubation. The crude MnP was 2.1-fold purified with a specific activity of 860 U/mg after purification on a Sephadex-G-100 gel column. On native and SDS-PAGE electrophoresis gels, the purified MnP fraction was a single homogenous band of 45 kDa. An active fraction of MnP was immobilized using hydrophobic sol-gel entrapment comprising tetramethoxysilane (T) and propyltrimethoxysilane (P) at different T:P molar ratios. Characterization revealed that after 24 h incubation at varying pH and temperatures, the MnP fraction immobilized at a T:P ratio of 1:2 in the sol-gel retained 82% and 75% of its original activity at pH4 and 70 ℃, respectively. The optimally active fraction at a 1:2 T:P ratio was tested against MnSO4 as a substrate to determine the kinetic catalytic constants KM and Vmax . To explore the industrial applicability of P. ostreatus IBL-02 MnP, both the free and immobilized MnP were used for the decolorization of four different textile industrial effluents. A maximum of 100% decolorization was achieved for the different textile effluents within the shortest time period. A lower KM , higher Vmax , hyper-activation, and enhanced acidic and thermal resistance up to 70 ℃ were the novel catalytic features of the sol-gel immobilized MnP, suggesting that it may be a potential candidate for biotechnological applications particularly for textile bioremediation purposes. 相似文献
62.
Hai-Bo Qiu Xin-Ya ChenQing Li Wen-Jian QianShun-Ming Yu Gong-Li TangZhu-Jun Yao 《Tetrahedron letters》2014
A practical HPLC-free total synthesis of chlorofusin has been successfully accomplished in this work. The new synthesis showed great flexibility and convenience in generating artificial natural product-like mimics through Click chemistry, and enabled us to further investigate the biological importance of the chromophore and the spiro-aminal functionality of the natural product. The entire skeleton is believed to be essential for satisfactory biological activities of both natural chlorofusin and unnatural mimics. Two artificial Click hybrids were found to exhibit improved inhibitory activity against p53–HDM2 bindings over the natural product. 相似文献
63.
Qun Dang Zhibo Zhang Shuangsheng He Yaohong Liu Tongqian Chen Stephane Bogen Vinay Girijavallabhan David B. Olsen Peter T. Meinke 《Tetrahedron letters》2014
To discover novel nucleosides as potential antiviral agents, 4′-spirocyclic phosphono-nucleosides were designed to mimic the monophosphate of R-1479, a known nucleoside inhibitor of HCV NS5B. Bypassing the first kinase step to nucleoside monophosphate is viewed as advantageous since this phosphorylation is often observed as the rate-limiting transformation to the active NTP for many nucleosides. Efficient synthetic routes were developed with a triphenylphosphine–iodine cyclization reaction as the key step to form the tetrahydrofuran 4′-spirocycle. The desired 4′-spirocyclic phosphono-cytidine analogs 12a, 12b, and 16 were prepared in 11 steps. 相似文献
64.
利用水热法和直接沉淀法, 设计合成了5例由过渡金属(TM)-联咪唑配阳离子与Dawson型钨磷酸阴离子构成的多金属氧酸盐(POM)基有机-无机杂化化合物[Ni(H2biim)3]4[Ni(H2biim)2(P2W18O62)2]·2H2O(1), [CoIII(H2biim)3]2[P2W18O62]·8H2O(2), [Cu(H2biim)2]3[P2W18O62]·4H2O(3), [CoII(H2biim)3]2H2[P2W18O62]·9H2O(4)和 [Ni(H2biim)3]3[P2W18O62]·2H2O(5); 并利用X射线单晶衍射分析(SC-XRD)、 红外光谱(IR)和热重-差热分析 (TG-DTA)等对其进行了表征. 化合物1~5作为载体用于固定辣根过氧化物酶(HRP)时, 显示出了较高的酶固定化能力. 另外, 利用圆二色光谱(CD)和激光扫描共聚焦显微镜(LSCM)等方法评价了固定化酶HRP/1~HRP/5的重复使用性、 储存稳定性和检测过氧化氢(H2O2)的性能. 由于该类POMs与HRP间存在强的相互作用, 利用简单的物理吸附法即可实现POMs对HRP的固载. POMs对酶的固定不但提高了HRP对使用及储存环境的耐受性, 同时也拓展了POMs在酶固定化领域的应用. 相似文献
65.
制备了一种具有过氧化物酶活性的类普鲁士蓝/氧化石墨烯复合纳米材料(CoFe(Ⅲ)PBA/GO)。将具有过氧化物酶活性的CoFe(Ⅲ)PBA/GO和化学发光法相结合,构建了一种用于检测H2O2和抗坏血酸(AA)的化学发光分析法。CoFe(Ⅲ)PBA/GO催化H2O2产生的O2·-,·OH,1O2自由基氧化Luminol会产生很强的化学发光信号,通过检测化学发光强度可以实现对H2O2的检测。该方法检测H2O2的线性范围为0~0.8μmol/L,检测限为11 nmol/L。利用AA作为活性氧消除剂可以抑制化学发光反应的特点,实现了AA的检测。该方法测定AA的线性范围为0.02~0.8μmol/L,检测限为20 nmol/L。方法已应用于H2O2消毒水中H2O2和维生素C片中抗坏血酸的检测。 相似文献
66.
67.
A novel photoelectrochemcial biosensing system was fabricated based on the composition of horseradish peroxidase (HRP), flower‐like CuInS2 (CIS) and graphene on indium tin oxide (ITO) electrode for detecting H2O2. The graphene layer was used as highly conductive scaffolds for electron transport from the ITO electrode to CIS. Furthermore, the flower‐like CIS enhanced the multi‐reflection of light and provided matrixes for the adsorption of HRP. Utilizing one‐pot solvothermal method, we prepared flower‐like CIS‐graphene hybrid (GCIS). Electrochemical tests displayed advantage of graphene with better electron conductivity, and HRP/GCIS showed higher photoelectrochemical behavior. 相似文献
68.
Strong ionic interactions in noncovalent complexes between poly(ethylene imine), a cationic electrolyte,and Cibacron Blue,a nucleotide mimic – implications for oligonucleotide vectors 下载免费PDF全文
Ömür Çelikbıçak Bekir Salih Chrys Wesdemiotis 《Journal of mass spectrometry : JMS》2014,49(7):597-607
Cationic polymers can bind DNA to form polyplexes, which are noncovalent complexes used for gene delivery into the targeted cells. For more insight on such biologically relevant systems, the noncovalent complexes between the cationic polymer poly(ethylene imine) (PEI) and the nucleotide mimicking dye Cibacron Blue F3G‐A (CB) were investigated using mass spectrometry methods. Two PEIs of low molecular weight were utilized (Mn ≈ 423 and 600 Da). The different types of CB anions produced by Na+/H+ exchanges on the three sulfonic acid groups of CB and their dehydrated counterparts were responsible for complex formation with PEI. The CB anions underwent noncovalent complex formation with protonated, but not with sodiated PEI. A higher proportion of cyclic oligomers were detected in PEI423 than PEI600, but both architectures formed association products with CB. Tandem mass spectrometry studies revealed a significantly stronger noncovalent interaction between PEI and dehydrated CB than between PEI and intact CB. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
69.
Xiaonan Duan Dr. Stéphane C. Corgié Prof. Daniel J. Aneshansley Prof. Peng Wang Prof. Larry P. Walker Prof. Emmanuel P. Giannelis 《Chemphyschem》2014,15(5):974-980
We report a new family of hierarchical hybrid catalysts comprised of horseradish peroxidase (HRP)–magnetic nanoparticles for advanced oxidation processes and demonstrate their utility in the removal of phenol from water. The immobilized HRP catalyzes the oxidation of phenols in the presence of H2O2, producing free radicals. The phenoxy radicals react with each other in a non‐enzymatic process to form polymers, which can be removed by precipitation with salts or condensation. The hybrid peroxidase catalysts exhibit three times higher activity than free HRP and are able to remove three times more phenol from water compared to free HRP under similar conditions. In addition, the hybrid catalysts reduce substrate inhibition and limit inactivation from reaction products, which are common problems with free or conventionally immobilized enzymes. Reusability is improved when the HRP–magnetic nanoparticle hybrids are supported on micron‐scale magnetic particles, and can be retained with a specially designed magnetically driven reactor. The performance of the hybrid catalysts makes them attractive for several industrial and environmental applications and their development might pave the way for practical applications by eliminating most of the limitations that have prevented the use of free or conventionally immobilized enzymes. 相似文献
70.
Porous CuO micro‐/nanostructures with clean surface, prepared through Cu2(OH)2CO3 precursor followed by calcination in air, were proven to be an effective peroxidase mimic. They can quickly catalyze oxidation of the peroxidase substrate 3,3′,5,5′‐tetramethylbenzidine (TMB) in the presence of H2O2, producing a blue color. The obtained porous CuO micro‐/nanostructure have potential application in wastewater treatment. The apparent steady‐state kinetic parameter was studied with TMB as the substrate. In addition, the potential application of the porous CuO in wastewater treatment was demonstrated with phenol‐containing water as an example. Such investigation not only confirms the intrinsic peroxidase‐like activity of micro‐/nanostructured CuO, but also suggests its potential application in wastewater treatment. 相似文献