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11.
A novel substrate {Galβ1,4GlcNAcβ1,4GlcNAc-β-pNP [Gal(GlcNAc)2-β-pNP]} for assaying lysozyme activity has been designed using docking simulations and enzymatic synthesis via β-1,4-galactosyltransferase-mediated transglycosylation from UDP-Gal as the donor to (GlcNAc)2-β-pNP as the acceptor. Hydrolysis of the synthesized Gal(GlcNAc)2-β-pNP and related compounds using hen egg-white lysozyme (HEWL) demonstrated that the substrate was specifically cleaved to Gal(GlcNAc)2 and p-nitrophenol (pNP). A combination of kinetic studies and docking simulation was further conducted to elucidate the mode of substrate binding. The results demonstrate that Gal(GlcNAc)2-β-pNP selectively binds to a subsite of lysozyme to liberate the Gal(GlcNAc)2 and pNP products. The work therefore describes a new colorimetric method for quantifying lysozyme on the basis of the determination of pNP liberated from the substrate. 相似文献
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13.
Tetsuya Nanba Shouichi Masukawa Atsushi Ogata Junko Uchisawa Akira Obuchi 《Applied catalysis. B, Environmental》2005,61(3-4):288-296
The catalytic decomposition of acrylonitrile (AN) over Cu-ZSM-5 prepared with various Cu loadings was investigated. AN conversion, during which the nitrogen atoms in AN were mainly converted to N2, increased as Cu loading increased. N2 selectivities as high as 90–95% were attained. X-ray diffraction measurements (XRD) and temperature-programmed reduction by H2 (H2-TPR) showed the existence of bulk CuO in Cu-ZSM-5 with a Cu loading of 6.4 wt% and the existence of highly dispersed CuO in Cu-ZSM-5 with a Cu loading of 3.3 wt%. Electron spin resonance measurements revealed that Cu-ZSM-5 contains three forms of isolated Cu2+ ions (square-planar, square-pyramidal, and distorted square-pyramidal). The H2-TPR results suggested that in Cu-ZSM-5 with a Cu loading of 2.9 wt% and below, Cu+ existed even after oxidizing pretreatment. The activity of AN decomposition over Cu/SiO2 suggested that CuO could form N2, but, independent of the CuO dispersion, nitrogen oxides (NOx) were formed above 350 °C. Cu+ and the square-pyramidal and distorted square-pyramidal forms of Cu2+ showed low activity for AN decomposition. Temperature-programmed desorption of NH3 suggested that N2 formation from NH3 proceeded on Cu2+, resulting in the formation of Cu+. The Cu+ ions were oxidized to Cu2+ at around 300 °C. Thus, high N2 selectivity over Cu-ZSM-5 with a wide range of temperature was probably attained by the reaction over the square-planar Cu2+, which can be reversibly reduced and oxidized. 相似文献
14.
Seung-Min Oh Hyun-Ha Kim Atsushi Ogata Hisahiro Einaga Shigeru Futamura Dong-Wha Park 《Catalysis Letters》2005,99(1-2):101-104
Toluene was decomposed in a surface discharge plasma reactor packed with various zeolites. The positioning effect of the zeolite bed was also investigated Reactor-B, in which the zeolite bed was located upstream, performed much better than Reactor-A, in which the zeolite bed was located downstream. Furthermore, the decomposition efficiency in Reactor-B increased with the capacity for toluene adsorption on zeolite, while that in Reactor-A did not. The toluene adsorbed in micropores was not decomposed effectively by direct electron impact, but was decomposed by active oxygen species generated in the plasma zone on the zeolite surface. A good correlation was also observed between toluene decomposition and ozone consumption in the downward-type reactor. 相似文献
15.
Mohammad Kamruzzaman Yutaka Kuwahara Tomonari Ogata Seiji Ujiie Seiji Kurihara 《Polymer International》2011,60(5):730-737
A new class of liquid‐crystalline poly(ethylene imine)s (PEIs) having four differently substituted (? CN,? C4H9,? OCH3 and? NO2) azobenzene side‐chain groups attached through alkyl spacer groups were successfully synthesized using a solution polycondensation reaction. The synthesized polymers were characterized using differential scanning calorimetry, polarized optical microscopy and X‐ray diffraction. The photochemical, thermo‐optical and photo‐orientational behavior of the polymers were investigated in detail. Spin‐coated films of PEIs with azobenzene groups having? C4H9,? OCH3 and? NO2 substituents showed out‐of‐plane molecular orientation on annealing. Except for the PEI with an azobenzene group having ? NO2 substituent, all polymers exhibited good photoresponsive properties upon irradiation with UV and visible light. Films of PEIs with azobenzene side groups having? CN,? C4H9 and? OCH3 substituents showed reversible alignment behavior from random state to out‐of‐plane and from out‐of‐plane to random state on annealing and on irradiation with UV and non‐polarized visible light. The reversibility of the molecular orientation of PEIs from random state to out‐of‐plane and from out‐of‐plane to random state greatly depended on the substituent attached to the azobenzene side‐chain group. Copyright © 2010 Society of Chemical Industry 相似文献
16.
Circular data are those for which the natural support is the unit circle and its toroidal extensions. Numerous constructions have been proposed which can be used to generate models for such data. We propose a new, very general, one based on the normalization of the spectra of complex-valued stationary processes. As illustrations of the new construction's application, we study models for univariate circular data obtained from the spectra of autoregressive moving average models and relate them to existing models in the literature. We also propose and investigate multivariate circular models obtained from the high-order spectra of stationary stochastic processes generated using linear filtering with an autoregressive moving average response function. A new family of distributions for a Markov process on the circle is also introduced. Results for asymptotically optimal inference for dependent observations on the circle are presented which provide a new paradigm for inference with circular models. The application of one of the new families of spectra-generated models is illustrated in an analysis of wind direction data. 相似文献
17.
Akiko Suzuki Mina Minamide Chihiro Iwaya Kenichi Ogata Junichi Iwata 《International journal of molecular sciences》2020,21(23)
Carbohydrates, fats, and proteins are the underlying energy sources for animals and are catabolized through specific biochemical cascades involving numerous enzymes. The catabolites and metabolites in these metabolic pathways are crucial for many cellular functions; therefore, an imbalance and/or dysregulation of these pathways causes cellular dysfunction, resulting in various metabolic diseases. Bone, a highly mineralized organ that serves as a skeleton of the body, undergoes continuous active turnover, which is required for the maintenance of healthy bony components through the deposition and resorption of bone matrix and minerals. This highly coordinated event is regulated throughout life by bone cells such as osteoblasts, osteoclasts, and osteocytes, and requires synchronized activities from different metabolic pathways. Here, we aim to provide a comprehensive review of the cellular metabolism involved in bone development and homeostasis, as revealed by mouse genetic studies. 相似文献
18.
We prepared a composite gel fiber by the gel formation of cellulose acetate and zirconium tetra-n-butoxide. Gel fiber is stable in common solvents, phosphate solution, and electrolyte solution. Invertase was entrap-immobilized on the gel fiber. The immobilization was easily performed under the mild conditions. The apparent Michaelis constant (Km) and maximum reaction velocity (Vmax) were estimated from Eadie–Hofstee plot for immobilized invertase. The Km of immobilized invertase was larger than that of native invertase, while the opposite tendency was observed for the Vmax. The activity for the immobilized invertase became higher with increasing fiber diameter. It indicates that the hydrolysis of sucrose occurs in the neighborhood of the fiber surface. The thermal stability of the immobilized invertase was higher than those of its native counterpart. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 2084–2088, 2001 相似文献
19.
20.
The dehydrofluorination of poly(vinylidene fluoride) (PVDF) powder and films was studied using several kinds of base solution. Especially the reactivity of 1,8-diazabicyclo[5.4.0]-7-undecene (DBU) in ethanol, KOH in 2-propanol and aqueous NaOH solution with tetrabutylammonium bromide was investigated by the change in infrared (IR) and ultraviolet-visible (UV-VI) absorptions of PVDF films. The elimination reactions by DBU or KOH were considered to be accompanied by substitution reaction. The electrical conductivity of dehydrofluorinated PVDF films increased markedly by doping with iodine, and the activation energies of conduction were found to be between 0.4 and 0.5 eV. When a drawn PVDF film was dehydrofluorinated and doped with iodine, anisotropy in conductivity was observed. 相似文献