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81.
Vindi M. Jayasinghe-Arachchige Qiaoyu Hu Gaurav Sharma Thomas J. Paul Marcus Lundberg David Quinonero Tatjana N. Parac-Vogt Rajeev Prabhakar 《Journal of computational chemistry》2019,40(1):51-61
In this study, mechanisms of hydrolysis of all four chemically diverse cleavage sites of human serum albumin (HSA) by [Zr(OH)(PW11O39)]4− (ZrK) have been investigated using the hybrid two-layer QM/MM (ONIOM) method. These reactions have been proposed to occur through the following two mechanisms: internal attack (IA) and water assisted (WA). In both mechanisms, the cleavage of the peptide bond in the Cys392-Glu393 site of HSA is predicted to occur in the rate-limiting step of the mechanism. With the barrier of 27.5 kcal/mol for the hydrolysis of this site, the IA mechanism is found to be energetically more favorable than the WA mechanism (barrier = 31.6 kcal/mol). The energetics for the IA mechanism are in line with the experimentally measured values for the cleavage of a wide range of dipeptides. These calculations also suggest an energetic preference (Cys392-Glu393, Ala257-Asp258, Lys313-Asp314, and Arg114-Leu115) for the hydrolysis of all four sites of HSA. © 2018 Wiley Periodicals, Inc. 相似文献
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85.
Rik Van Deun Peter Nockemann Tatjana N. Parac-Vogt Kristof Van Hecke Luc Van Meervelt Christiane Grller-Walrand Koen Binnemans 《Polyhedron》2007,26(18):5441-5447
The near-infrared luminescence properties of three (E)-N-hexadecyl-N′,N′-dimethylamino-stilbazolium tetrakis(1-phenyl-3-methyl-4-benzoyl-5-pyrazolonato) lanthanide(III) complexes are described. These three complexes, containing trivalent neodymium, erbium and ytterbium, respectively, show near-infrared luminescence in acetonitrile solution upon UV irradiation. Luminescence decay times have been measured. The complexes consist of a positively charged hemicyanine chromophore with a long alkyl chain and a tetrakis(pyrazolonato) lanthanide(III) anion. Because of the absence of an -hydrogen atom in the pyrazolonato ligands, and because of the saturation of the coordination sphere by four bidentate ligands, the luminescence properties are enhanced when compared to, e.g. quinolinate complexes. 相似文献
86.
Different capillary electrophoretic techniques were investigated and compared for the separation of low-molecular-mass phenolic
and neutral lignin degradation compounds. Simple capillary zone electrophoresis (CZE) was not suited for this problem. Switching
to micellar electrokinetic capillary chromatography (MEKC) by adding micelle-forming reagents to the carrier electrolyte enhanced
the separation performance considerably. Alternatively, microemulsion electrokinetic chromatography (MEEKC) was investigated.
This is a CE technique in which analytes interact with moving oil droplets present in a microemulsion buffer. Using the optimized
carrier electrolyte systems and a 60 cm×50 μm I.D. bubble cell capillary it was possible to analyse solutions of different
wood digestion procedures and to investigate differences in lignin degradation products during use of different kinds of wood
(eucalyptus, beech, scotch pine and acacia).
Received August 25, 1999. Revision April 13, 2000 相似文献
87.
Peter Nockemann Dr. Michael Pellens Kristof Van Hecke Dr. Luc Van Meervelt Prof. Dr. Johan Wouters Prof. Dr. Ben Thijs Dr. Evert Vanecht Tatjana N. Parac‐Vogt Prof. Dr. Hasan Mehdi Stijn Schaltin Jan Fransaer Prof. Dr. Stefan Zahn Barbara Kirchner Prof. Dr. Koen Binnemans Prof. Dr. 《Chemistry (Weinheim an der Bergstrasse, Germany)》2010,16(6):1849-1858
A series of nitrile‐functionalized ionic liquids were found to exhibit temperature‐dependent miscibility (thermomorphism) with the lower alcohols. Their coordinating abilities toward cobalt(II) ions were investigated through the dissolution process of cobalt(II) bis(trifluoromethylsulfonyl)imide and were found to depend on the donor abilities of the nitrile group. The crystal structures of the cobalt(II) solvates [Co(C1C1CNPyr)2(Tf2N)4] and [Co(C1C2CNPyr)6][Tf2N]8, which were isolated from ionic‐liquid solutions, gave an insight into the coordination chemistry of functionalized ionic liquids. Smooth layers of cobalt metal could be obtained by electrodeposition of the cobalt‐containing ionic liquids. 相似文献
88.
Tatjana M. Trtić‐Petrović Ksenija R. Kumrić Jelena S. Đorđević Goran T. Vladisavljević 《Journal of separation science》2010,33(13):2002-2009
Transport behaviour of Lu(III) across a polypropylene hollow fibre‐supported liquid membrane containing di(2‐ethylhexyl)phosphoric acid (DEHPA) in dihexyl ether as a carrier has been studied. The donor phase was LuCl3 in the buffer solution consisting of 0.2 M sodium acetate at pH 2.5–5.0. A miniaturised system with a single hollow fibre has been operated in a batch mode. The concentration of Lu(III) was determined by indirect voltammetric method using Zn–EDTA complex. The effect of pH and volume of the donor phase, DEHPA concentration in the organic (liquid membrane) phase, the time of extraction and the content of the acceptor phase on the Lu(III) extraction and stripping behaviour was investigated. The results were discussed in terms of the pertraction and removal efficiency, the memory effect and the mean flux of Lu(III). The optimal conditions for the removal of 177Lu(III) from labelled 177Lu‐radiopharmaceuticals were discussed and identified. The removal efficiency of Lu(III) greater than 99% was achieved at pH of the donor phase between 3.5 and 5.0 using DEHPA concentration in the organic phase of 0.47 M and the ratio of the donor to the acceptor phase of 182. 相似文献
89.
Ljiljana Pavlovi? Mirjana Lazi? Tatjana Aleksi? 《Discrete Applied Mathematics》2009,157(13):2938-2944
Let G be a graph and d(u) denote the degree of a vertex u in G. The zeroth-order general Randi? index 0Rα(G) of the graph G is defined as ∑u∈V(G)d(u)α, where the summation goes over all vertices of G and α is an arbitrary real number. In this paper we correct the proof of the main Theorem 3.5 of the paper by Hu et al. [Y. Hu, X. Li, Y. Shi, T. Xu, Connected (n,m)-graphs with minimum and maximum zeroth-order general Randi? index, Discrete Appl. Math. 155 (8) (2007) 1044-1054] and give a more general Theorem. We finally characterize 1 for α<0 the connected G(n,m)-graphs with maximum value 0Rα(G(n,m)), where G(n,m) is a simple connected graph with n vertices and m edges. 相似文献
90.
Victor M. Karpov Vyacheslav E. Platonov Tatjana V. Rybalova Yuri V. Gatilov Makhmut M. Shakirov 《Journal of fluorine chemistry》2006,127(7):936-942
Acetic acid-catalyzed condensation of 2-amino-3-(1-imino-2,2,2-trifluoroethyl)-1,1,4,5,6,7-hexafluoroindene (1b) with acetone and cyclopentanone gives 5,6,7,8,9,9-hexafluoro-2,2-dimethyl-4-trifluoromethyl-2,3-dihydro-1,3-diazafluorene (2a) and 5,6,7,8,9,9-hexafluoro-4-trifluoromethyl-2,3-dihydro-1,3-diazafluorene-2-spiro-1′-cyclopentane (3a) together with small amounts of 5,6,7,8,9,9-hexafluoro-2,2-dimethyl-4-trifluoromethyl-1,2-dihydro-1,3-diazafluorene (2b) and 5,6,7,8,9,9-hexafluoro-4-trifluoromethyl-1,2-dihydro-1,3-diazafluorene-2-spiro-1′-cyclopentane (3b), respectively. When acted upon by (CH3)2SO4 compounds 2, 3 were converted into corresponding fluorine-containing 1-methyl-1,2-dihydro-1,3-diazafluorenes 6, 7. 4a-Chloro-5,6,7,8,9,9-hexafluoro-2,2-dimethyl-4-trifluoromethyl-2,4a-dihydro-1,3-diazafluorene (8) has been synthesized by the interaction of compound 2 with SOCl2. Solution of compound 2 as well as 8 in CF3SO3H-CD2Cl2 generated 5,6,7,8,9,9-hexafluoro-2,2-dimethyl-4-trifluoromethyl-1,2,3,4-tetrahydro-1,3-diazafluorene-4-yl cation (2c). The structures of compounds 2, 3, 6-8 have been determined by single crystal X-ray diffraction. 相似文献