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121.
Claire André Iva Kapustikova Lydie Lethier Yves Claude Guillaume 《Chromatographia》2014,77(21-22):1521-1527
The arginase enzyme was bound to porous silica using a reactive polymer where two types of nanomaterials were entrapped, i.e., carbon nanotubes (CNTs) and boron nitride nanotubes (BNNTs). For the first time, it was shown that BNNTs were highly efficient for increasing the performance of a particulate bioactive support. Also, we demonstrated that BNNTs enhanced more strongly this effect in comparison with CNTs. In addition, with this novel bioactive support, the relative IC50 values of the well-known arginase inhibitors were found to be in agreement with those derived by the conventional spectrometric method. It was shown the ethylacetate extract of the roots of Spirotropis longifolia (SL) and of the ethanol extract of sunflower (Helianthus annuus) seed (SS) and Lonicera japonica Thunb, i.e., honeysuckle (H) on the arginase activity inhibited the enzyme activity. 相似文献
122.
Morphine-6-glucuronide (M6G) is the primarily active metabolite of morphine, produced endogenously by the UGT enzyme, which displays analgesic activity. For this reason, M6G is a promising drug candidate for the treatment of severe pain. We described herein a new, efficient and scalable synthesis of M6G using dimorphinic derivatives. This preparation of M6G could be performed on multigram scale with good yield and high purity. 相似文献
123.
Tang C Ulijn RV Saiani A 《Langmuir : the ACS journal of surfaces and colloids》2011,27(23):14438-14449
We have investigated the self-assembly behavior of fluorenyl-9-methoxycarbonyl (Fmoc)-FG, Fmoc-GG, and Fmoc-GF and compared it to that of Fmoc-FF using potentiometry, fluorescence and infrared spectroscopy, transmission electron microscopy, wide-angle X-ray scattering, and oscillatory rheometry. Titration experiments revealed a substantially shifted apparent pK(a) transition for Fmoc-FG, Fmoc-GG, and Fmoc-GF. The apparent pK(a) values observed correlated with the hydrophobicity (log P) of the Fmoc-dipeptide molecules. Fmoc-GG and Fmoc-GF were found to self-assemble only in their protonated form (below their apparent pK(a)), while Fmoc-FG formed self-assembled structures above and below its apparent pK(a). Fmoc-GG and Fmoc-FG were found to form hydrogels below their apparent pK(a) transitions in agreement with the entangled fibers morphologies revealed by TEM. Unlike Fmoc-FF and Fmoc-GG, Fmoc-FG showed unusual gelation behavior as gels were found to form upon heating. Fmoc-GF formed precipitates instead of a hydrogel below its apparent pK(a) in agreement with the formation of micrometer scale sheetlike structures observed by TEM. The fact that all four Fmoc-dipeptides were found to self-assemble suggests that the main driving force behind the self-assembly process is a combination of the hydrophobic and π-π interactions of the fluorenyl moieties with a secondary role for hydrogen bonding of the peptidic components. The nature of the peptidic tail was found to have a pronounced effect on the type of self-assembled structure formed. This work indicates that the substitution of phenylalanine by glycine significantly impacts on the mode of assembly and illustrates the versatility of aromatic peptide amphiphiles in the formation of structurally diverse nanostructures. 相似文献
124.
The current work describes the elaboration of a simple, sensitive and reliable β-casein modified glass beads, for the detection and quantification of its specific antibody anti β-casein. This is an elementary receptor without electronic part, developed by grafting glass bead surface with the antigenic β-casein via 3-aminopropyltriethoxy silane and then glutaraldehyde as cross-linker. The whole is realized by a classical process, called in two steps and in mild conditions where chemical protocol is optimized for β-casein use. The detection and quantification of the specific reaction antibody-receptor is carried out by the technique of the second antibody labeled with horse radish peroxidase (HRP). Our receptor can detect the β-casein antibody present in the serum at dilutions up to a factor 107 in strong ionic strength medium. The same antibody of the same serum and in the same conditions can be detected by ELISA test at dilutions up to a factor 105. The whole test, after our receptor realization, takes about 5 h. 相似文献
125.
Boehner CM Frye EC O'Connell KM Galloway WR Sore HF Dominguez PG Norton D Hulcoop DG Owen M Turner G Crawford C Horsley H Spring DR 《Chemistry (Weinheim an der Bergstrasse, Germany)》2011,17(47):13230-13239
The prevalence of the biaryl structural motif in biologically interesting and synthetically important molecules has inspired considerable interest in the development of methods for aryl-aryl bond formation. Herein we describe a novel strategy for this process involving the fluoride-free, palladium-catalysed cross-coupling of readily accessible aryldisiloxanes and aryl bromides. Using a statistical-based optimisation process, preparatively useful reaction conditions were formulated to allow the cross-coupling of a wide range of different substrates. This methodology represents an attractive, cost-efficient, flexible and robust alternative to the traditional transition-metal-catalysed routes typically used to generate molecules containing the privileged biaryl scaffold. 相似文献
126.
Stephen E Huang D Shaw JL Blake AJ Collison D Davies ES Edge R Howard JA McInnes EJ Wilson C Wolowska J McMaster J Schröder M 《Chemistry (Weinheim an der Bergstrasse, Germany)》2011,17(37):10246-10258
The NiII complexes [Ni([9]aneNS2‐CH3)2]2+ ([9]aneNS2‐CH3=N‐methyl‐1‐aza‐4,7‐dithiacyclononane), [Ni(bis[9]aneNS2‐C2H4)]2+ (bis[9]aneNS2‐C2H4=1,2‐bis‐(1‐aza‐4,7‐dithiacyclononylethane) and [Ni([9]aneS3)2]2+ ([9]aneS3=1,4,7‐trithiacyclononane) have been prepared and can be electrochemically and chemically oxidized to give the formal NiIII products, which have been characterized by X‐ray crystallography, UV/Vis and multi‐frequency EPR spectroscopy. The single‐crystal X‐ray structure of [NiIII([9]aneNS2‐CH3)2](ClO4)6?(H5O2)3 reveals an octahedral co‐ordination at the Ni centre, while the crystal structure of [NiIII(bis[9]aneNS2‐C2H4)](ClO4)6?(H3O)3? 3H2O exhibits a more distorted co‐ordination. In the homoleptic analogue, [NiIII([9]aneS3)2](ClO4)3, structurally characterized at 30 K, the Ni? S distances [2.249(6), 2.251(5) and 2.437(2) Å] are consistent with a Jahn–Teller distorted octahedral stereochemistry. [Ni([9]aneNS2‐CH3)2](PF6)2 shows a one‐electron oxidation process in MeCN (0.2 M NBu4PF6, 293 K) at E1/2=+1.10 V versus Fc+/Fc assigned to a formal NiIII/NiII couple. [Ni(bis[9]aneNS2‐C2H4)](PF6)2 exhibits a one‐electron oxidation process at E1/2=+0.98 V and a reduction process at E1/2=?1.25 V assigned to NiII/NiIII and NiII/NiI couples, respectively. The multi‐frequency X‐, L‐, S‐, K‐band EPR spectra of the 3+ cations and their 86.2 % 61Ni‐enriched analogues were simulated. Treatment of the spin Hamiltonian parameters by perturbation theory reveals that the SOMO has 50.6 %, 42.8 % and 37.2 % Ni character in [Ni([9]aneNS2‐CH3)2]3+, [Ni(bis[9]aneNS2‐C2H4)]3+ and [Ni([9]aneS3)2]3+, respectively, consistent with DFT calculations, and reflecting delocalisation of charge onto the S‐thioether centres. EPR spectra for [61Ni([9]aneS3)2]3+ are consistent with a dynamic Jahn–Teller distortion in this compound. 相似文献
127.
Park KD Kim D Reamtong O Eyers C Gaskell SJ Liu R Kohn H 《Journal of the American Chemical Society》2011,133(29):11320-11330
We have advanced a useful strategy to elucidate binding partners of ligands (drugs) with modest binding affinity. Key to this strategy is attaching to the ligand an affinity bait (AB) and a chemical reporter (CR) group, where the AB irreversibly attaches the ligand to the receptor upon binding and the CR group is employed for receptor detection and isolation. We have tested this AB&CR strategy using lacosamide ((R)-1), a low-molecular-weight antiepileptic drug. We demonstrate that using a (R)-lacosamide AB&CR agent ((R)-2) 14-3-3 ζ in rodent brain soluble lysates is preferentially adducted, adduction is stereospecific with respect to the AB&CR agent, and adduction depends upon the presence of endogenous levels of the small molecule metabolite xanthine. Substitution of lacosamide AB agent ((R)-5) for (R)-2 led to the identification of the 14-3-3 ζ adduction site (K120) by mass spectrometry. Competition experiments using increasing amounts of (R)-1 in the presence of (R)-2 demonstrated that (R)-1 binds at or near the (R)-2 modification site on 14-3-3 ζ. Structure-activity studies of xanthine derivatives provided information concerning the likely binding interaction between this metabolite and recombinant 14-3-3 ζ. Documentation of the 14-3-3 ζ-xanthine interaction was obtained with isothermal calorimetry using xanthine and the xanthine analogue 1,7-dimethylxanthine. 相似文献
128.
Hansell CF Espeel P Stamenović MM Barker IA Dove AP Du Prez FE O'Reilly RK 《Journal of the American Chemical Society》2011,133(35):13828-13831
Herein we report the use of a tetrazine-norbornene inverse electron demand Diels-Alder conjugation applied to polymer end-functionalization and polymer-polymer coupling. The reaction was found to be applicable to polymer-polymer coupling, as judged by SEC, DOSY NMR, and LCxSEC analyses, giving diblock copolymers by merely mixing the constituent homopolymers together under ambient conditions, using no catalyst, additive, or external stimulus. 相似文献
129.
Carter CL McLeod CW Bunch J 《Journal of the American Society for Mass Spectrometry》2011,22(11):1991-1998
Matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) is a valuable tool for the analysis of molecules
directly from tissue. Imaging of phospholipids is gaining widespread interest, particularly as these lipids have been implicated
in a variety of pathologic processes. Formalin fixation (FF) is the standard protocol used in histology laboratories worldwide
to preserve tissue for analysis, in order to aid in the diagnosis and prognosis of diseases. This study assesses MALDI imaging
of phospholipids directly in formalin fixed tissue, with a view to future analysis of archival tissue. This investigation
proves the viability of MALDI-MSI for studying the distribution of lipids directly in formalin fixed tissue, without any pretreatment
protocols. High quality molecular images for several phosphatidylcholine (PC) and sphingomyelin (SM) species are presented.
Images correspond well with previously published data for the analysis of lipids directly from freshly prepared tissue. Different
ionization pathways are observed when analyzing fixed tissue compared with fresh, and this change was found to be associated
with formalin buffers employed in fixation protocols. The ability to analyze lipids directly from formalin fixed tissue opens
up new doors in the investigation of disease profiles. Pathologic specimens taken for histologic investigation can be analyzed
by MALDI-MS to provide greater information on the involvement of lipids in diseased tissue. 相似文献
130.
Hybrids of vinblastine and phomopsin, designed by a molecular modelling study, were elaborated in order to target tubulin. The key step of the synthesis (fragmentation and insertion of vindoline) was mediated by an internal N-carboxyanhydride (or O-acylcarbamate). This reaction was diastereospecific and addition of silver salts could reverse the diastereoselectivity. Even if the synthesized compounds are inactive, this synthesis represents an original example of a C-N fragmentation mediated by a N-carboxyanhydride. 相似文献