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排序方式: 共有1876条查询结果,搜索用时 15 毫秒
91.
Dr. Kenichiro Ito Dr. Yoshihiko Matsuda Ayako Mine Kyohei Miyairi Dr. Yoshimi Kikuchi Dr. Atsushi Konishi 《Chembiochem : a European journal of chemical biology》2023,24(2):e202200599
The inhibition of protein-protein interactions (PPIs) is an effective approach for therapy. Owing to their large binding surface areas to target proteins, macrocyclic peptides are suitable molecules for PPI inhibition. In this study, we developed single-chain tandem macrocyclic peptides (STaMPtides) that inhibits the vascular endothelial growth factor (VEGF) receptor 2 (VEGFR2). They were artificially designed to comprise two different VEGFR2-binding macrocyclic peptides linked in tandem by peptide linkers and secreted by Corynebacterium glutamicum. Most potent VEGFR2-inhibitory STaMPtides with length-optimized linkers exhibited >1000 times stronger inhibitory activity than their parental monomeric peptides, possibly due to the avidity effect of heterodimerization. Our approach of using STaMPtides for PPI inhibition may be used to inhibit other extracellular factors, such as growth factors and cytokines. 相似文献
92.
Jun-Ichiro Hayashi Masahiro IwatsukiKayoko Morishita Atsushi TsutsumiChun-Zhu Li Tadatoshi Chiba 《Fuel》2002,81(15):1977-1987
Two pairs of raw and acid-washed coal samples were prepared from Yallourn and Loy Yang brown coals, and subjected to rapid pyrolysis in a drop-tube reactor at 1073-1173 K in a stream of N2 or H2O/N2 mixture. Examinations were made on the roles of the inherent metallic species in the secondary reactions of nascent tar and char that were formed by the intraparticle primary reactions. The experimental results revealed that the inherent metallic species were essential for vary rapid steam reforming/gasification of the nascent tar/char and simultaneous suppression of soot formation. In the absence of the metallic species, the soot formation from the tar accounted as much as 15-19 and 6-13% of the carbon in coal in N2 and H2O/N2, respectively. The metallic species reduced the yield of soot to 6-8% in N2 by enhancing the reforming of tar by H2O generated from the pyrolysis of coal. In the H2O/N2 stream, instead of soot formation, a net gasification conversion up to 17% within 4.3 s was observed in the presence of the metallic species as a result of catalytic gasification of the nascent char. Moreover, the metallic species catalyzed the steam reforming of the nascent tar, giving its conversion up to 99%. Over the range of the conditions employed, a one-to-one stoichiometry was established between the steam consumption and the yield of carbon oxides formed by the steam reforming/gasification and water-gas-shift reaction. 相似文献
93.
Arai Kazuhito; Hishida Atsushi; Ishiyama Mariko; Kamata Takeo; Uchikoba Hiroyuki; Fushinobu Shinya; Matsuzawa Hiroshi; Taguchi Hayao 《Protein engineering, design & selection : PEDS》2002,15(1):35-41
Lactobacillus casei allosteric L-lactate dehydrogenase (L-LDH)absolutely requires fructose 1,6-bisphosphate [Fru(1,6)P2] forits catalytic activity under neutral conditions, but exhibitsmarked catalytic activity in the absence of Fru(1,6)P2 underacidic conditions through the homotropic activation effect ofsubstrate pyruvate. In this enzyme, a single amino acid replacement,i.e. that of His205 conserved in the Fru(1,6)P2-binding siteof certain allosteric L-LDHs of lactic acid bacteria with Thr,did not induce a marked loss of the activation effect of Fru(1,6)P2or divalent metal ions, which are potent activators that improvethe activation function of Fru(1,6)P2 under neutral conditions.However, this replacement induced a great loss of the Fru(1,6)P2-independentactivation effect of pyruvate or pyruvate analogs under acidicconditions, consequently indicating an absolute Fru(1,6)P2 requirementfor the enzyme activity. The replacement also induced a significantreduction in the pH-dependent sensitivity of the enzyme to Fru(1,6)P2,through a slight decrease and increase of the Fru(1,6)P2 sensitivityunder acidic and neutral conditions, respectively, indicatingthat His205 is also largely involved in the pH-dependent sensitivityof L.casei L-LDH to Fru(1,6)P2. The role of His205 in the allostericregulation of the enzyme is discussed on the basis of the knowncrystal structures of L-LDHs. 相似文献
94.
Atsushi Narumi Kosei Kawasaki Harumi Kaga Toshifumi Satoh Naoya Sugimoto Toyoji Kakuchi 《Polymer Bulletin》2003,49(6):405-410
Summary
The potato phosphorylase-catalyzed polymerization of α-D-glucose-1-phosphate (G-1-P) onto poly[styrene-block-(4-vinylbenzyl maltohexaoside)] (1) was performed at the molar ratios of [G-l-P]0 and [maltohexaose]0 of 35, 80, and 250. The product was found to be soluble in dimethyl sulfoxide, which was a good solvent for amylose, and
showed the complex-formation with iodine, indicating that the product was assignable to poly[styrene-block-(styrene-graft-amylose)] (2). The quantitative analysis of the liberated phosphoric acid gave the average degree of polymerization o f the glucose unit
(n) as 27, 5 1, and 180 for 2-I, 2-II, and 2-III, respectively.
Received: 29 November 2002/Accepted: 22 December 2002
Correspondence to Toyoji Kakuchi 相似文献
95.
The stepwise insertion reaction of styrene (St) and p-tert-butoxystyrene (BOSt) into poly(alkoxyamine) macroinitiator was carried out to provide well-defined poly(St)-b-poly(BOSt) multiblock copolymers. Structural confirmation of the multiblock copolymers was accomplished by NMR and IR measurements. The model reaction also supported that the monomer insertion into the macroinitiator proceeded in accordance with a living fashion. 相似文献
96.
This paper describes the effects of electrode configuration and the loading amount of Ag catalyst on the decomposition of gas-phase benzene using plasma-driven catalyst (PDC) reactors. Modification of ground electrode brought out a great enhancement in the energy efficiency for benzene decomposition by reducing abnormal discharges outside the reactor tube. The data of carbon balance and the selectivity of CO2 indicated that the Ag catalyst played an important role in the decomposition of benzene, especially for the intermediates. The larger the Ag-loading amounts on the TiO2, the better the performance of benzene decomposition in terms of the carbon balance and the selectivity of CO2. Formation of NO2 and N2O indicated that the maximum specific input energy applicable to the PDC reactor should be determined not only by the decomposition efficiency but also by the formation of nitrogen oxides. 相似文献
97.
Maxim Lebedev Jun Akedo Atsushi Iwata Satoshi Sugimoto Kouichiro Inomata 《Journal of the American Ceramic Society》2004,87(9):1621-1624
This paper describes the magnetic properties of NiZnCu ferrite film deposited at room temperature by an aerosol deposition method (ADM). The thickness of the film was 6 μm and the deposition rate was estimated as 2 μm/min. The microstructure of as-deposited at room temperature films consists of randomly oriented nanocrystallites with a size of 20 nm. As-deposited and annealed films exhibited the following magnetic properties: intensity of magnetization M s = 0.147 T (117 emu/cm3 ), coercivity H c = 40.58 kA/m (510 Oe); and M s = 0.3 T (250 emu/cm3 ), H c = 14.95 kA/m (188 Oe), respectively. 相似文献
98.
Isao Kobayashi Mitsutoshi Nakajima Hiroshi Nabetani Yuji Kikuchi Atsushi Shohno Kazumi Satoh 《Journal of the American Oil Chemists' Society》2001,78(8):797-802
Micron-scale monodisperse oil-in-water (O/W) micropheres (MS) were prepared using a novel microchannel (MC) emulsification
technique. The characteristics of the MS preparation and the O/W-MS prepared were studied. Soybean oil and medium-chain triacyglycerol
(MCT) were used as the disprrsed phase, and physiological saline was used as the continuous phase. Silicon MC with 1 to 3μm-equivalent
channel diameters were employed. A novel MC module was devised to easily recover the O/W-MS prepared. The effects of the channel
shape on the behavior of MS formation, on the MS size, and on the distribution were investigated. An MC with a terrace at
the MC outlet stably yielded micron-scale monodisperse O/W-MS; the MS had diameters of about 5 μm, and their coefficients
of variation were below 9%. Monodisperse food-grade O/W-MS with diameters of about 4 μm could be obtained by using polyglycerol
fatty acid ester as the surfactant. The size and size distribution of the recovered O/W-MS remained almost constant over 60
d, demonstrating their long-term stability. 相似文献
99.
Koganesawa Nozomi; Aizawa Tomoyasu; Masaki Kazuo; Matsuura Atsushi; Nimori Taisuke; Bando Hisanori; Kawano Keiichi; Nitta Katsutoshi 《Protein engineering, design & selection : PEDS》2001,14(9):705-710
Expression systems of human and silkworm lysozymes were constructedusing the methylotrophic yeast Pichia pastoris as a host. Theleader sequence and its prepro peptide of 相似文献
100.
Yusuke Yamada Atsushi Ueda Zhen Zhao Toru Maekawa Kengo Suzuki Tadashi Takada Tetsuhiko Kobayashi 《Catalysis Today》2001,67(4):325-387
The rapid evaluation of catalysis is an indispensable technology for the success of combinatorial chemistry. A small-sized, less expensive, easily operating screening is desirable for parallel settings which dramatically shortens the evaluation time. Recent advances in gas sensors have enabled us to use them for the rapid evaluation of oxidation catalysis. Three typical catalytic oxidations over metal oxide catalysts were evaluated by gas sensor systems optimized for each catalytic system. The first one is the total oxidation of carbon monoxide in air. Five catalytic combustion-type gas sensors were used in a parallel reactor system to shorten the evaluation time. The second one is the oxidative dehydrogenation (ODH) of ethane over the mixed oxide of nickel and iron. The evaluation of the ODH catalysis was performed by a selective olefin sensor which determines the concentration of C2H4 in C2H6. The third one is the selective oxidation catalysis of propane over alkali modified Fe/SiO2. The effluents including CO, CO2, aldehydes and ketones in propane were analyzed by the CO, CO2 and semiconductor-type gas sensors selective toward aldehydes and ketones. These evaluation results indicated that gas sensors have a good potential for the rapid evaluation of oxidation catalysts. 相似文献