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排序方式: 共有753条查询结果,搜索用时 15 毫秒
741.
Stancanelli R Crupi V De Luca L Ficarra P Ficarra R Gitto R Guardo M Iraci N Majolino D Tommasini S Venuti V 《Bioorganic & medicinal chemistry》2008,16(18):8706-8712
The (R,S)-2-acetyl-1-(4'-chlorophenyl)-6,7-dimethoxy-1,2,3,4-tetrahydroisoquinoline ((R,S)-1) was previously identified as a potent non-competitive AMPA receptor antagonist able to prevent epileptic seizures and reduce AMPA-induced current in electrophysiological experiments. Through the enantiomeric resolution of racemate by chiral HPLC we already demonstrated that the (R)-1 enantiomer was the eutomer. Considering the poor water solubility, these compounds have been complexed with beta-cyclodextrin (beta-CyD). The effect of beta-cyclodextrin on the spectral features of molecules was quantitatively investigated, in fully aqueous medium by phase-solubility study and the obtained diagrams suggested that it forms complexes with a molar ratio 1:1. The binding constant (K((R)-1)=15889M(-1), K((R,S)(-1))=1079 M(-1)) and the complexation efficiency (CE) were calculated. Then the solid complexes in 1:1 molar ratio were prepared by the co-precipitation method and the FTIR-ATR measurements were carried out in order to confirm the host-guest interactions that drive the complexation process, by monitoring the significant differences of the spectra of the complexes with respect to those of the corresponding physical mixtures in the same molar ratio. The experimental data have been compared with molecular modelling studies and we confirmed our hypothesis. 相似文献
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745.
Zhu Guofen; Jaskiewicz Ewa; Bassi Rosaria; Darling Douglas S.; Young William W. Jr. 《Glycobiology》1997,7(7):987-996
Many Golgi membrane-bound glycosyltransferases exist as intermoleculardisulfide bonded species, some of which have been demonstratedto be homodimers. Evidence for homodimer formation has comeprimarily from radiation inactivation experiments. We utilizedan alternative strategy to test for homodimer formation of thecloned ß1,4 N-acetylgalactosaminyltransferase (GalNAcT)responsible for synthesis of the glycosphingolipids GM2, GD2,and GA2. We stably transfected CHO cells with. myc epitope-taggedGalNAcT, which localizes primarily to the Golgi, and a hemagglutinin(HA) epitope-tagged GalNAcT fusion protein in which the cytoplasmicdomain of GalNAcT was replaced by an ER retention signal. Wethen sought evidence for dimer formation between the two formsof GalNAcT. Immunoprecipitation with anti-myc or anti-HA co-immunoprecipitatedthe HA-tagged form or the myc-tagged form, respectively, providingevidence for the physical association of the two forms of GalNAcT.As a result of this association, GalNAcT/myc increased in theER as demonstrated by Western blots and immunofluorescence.The rapid formation of dimers provided further evidence fordimer formation occurring in the ER. In summary, these resultsdemonstrate that GalNAcT forms homodimers as a result of intermoleculardisulfide bond formation in the ER. Furthermore, this ER motifstrategy is potentially useful for demonstrating homodimer formationof other Golgi enzymes. ganglioside glycosyltransferase 相似文献
746.
Freeze-fracture immunogold labeling 总被引:1,自引:1,他引:0
Several approaches have been developed to combine immunogold cytochemistry and freeze-fracture techniques. These methods
are highly heterogeneous regarding both the sequence of the procedural steps and the aspect of the resulting images. They
imply immunolabeling either before or after freeze-fracture or even immunolabeling of platinum/carbon replicas of the freeze-fractured
membranes, and have been used alternatively or in parallel to address different questions related to cell membrane structure,
composition and dynamics or to intracellular membrane traffic. This review will briefly describe these methods and report
most of their immunogold cytochemical applications, with the aim of facilitating selection of the most appropriate approach.
Accepted: 2 May 1996 相似文献
747.
The 7 kDa Sso7 is a basic protein particularly abundant in Sulfolobus solfataricus and is involved in DNA assembly. This protein undergoes in vitro ADP-ribosylation by an endogenous poly(ADP-ribose) polymerase-like enzyme. The circular dichroism spectrum of purified ADP-ribosylated Sso7 shows that this modification stabilizes the prevalent protein β-conformation, as suggested by shifting of negative ellipticity minimum to 220 nm. Moreover, a short ADP-ribose chain (up to 6-mers) bound to Sso7 is able to reduce drastically the thermoprotective and DNA condensing ability of the protein, suggesting a possible regulatory role of ADP-ribosylation in sulfolobal DNA organization. 相似文献
748.
A. Savoia Maria Rosaria Piemontese Maria Savino Adriana Zatterale J. Pronk F. Arwert Hans Joenje Ugo Ramenghi Franca Dagna-Bricarelli Bruno Dallapiccola Leopoldo Zelante 《Human genetics》1996,99(1):93-97
Fanconi anaemia (FA) is an autosomal recessive disease characterised by genetic heterogeneity, with at least five complementation
groups (FA-A to FA-E). The FAC gene has been cloned and localised to 9q22.3. The most frequent defective gene, FAA, was recently
mapped to chromosome 16q24.3, in a region of 10 cM between D16S498 and the telomere. Eleven FA-A and 16 unclassified Italian
families were analysed by microsatellite markers. To define the localisation of the FAA locus further, microsatellites were
analysed at 16q24. All the families were consistent with linkage, the highest lod score being observed with D16S1320. Evidence
for common haplotypes was obtained in two genetic isolates from the Brenta basin and the Naples region. Autozygosity mapping
and haplotype analysis suggest that the FAA locus is distal to D16S305.
Received: 29 July 1996 相似文献
749.
750.
Andrea Zattoni Pierluigi Reschiglian Nelsi Zaccheroni Rosaria Anna Picca 《Inorganica chimica acta》2007,360(3):1063-1071
Films based on TiO2 nanoparticles (NPs) have been successfully used as sensing elements in chemical sensors. TiO2 colloidal suspensions can be obtained by spontaneous hydrolysis in acidic solutions of Ti(IV) compounds. The obtained TiO2 NPs can be employed to build up nanostructured films. With the purpose of preparing TiO2-based nanostructured, imprinted materials as sensing elements for piezoelectric sensors, we obtained TiO2 NP dispersions by hydrolyzing potassium titanyl oxalate in the presence of a target analyte (tyrosine). Since morphological properties of the synthesized NPs are known to influence the nanostructured film characteristics, an analytical strategy to characterize such colloidal systems can combine a size-based separation method with spectroscopic analysis to correlate the particle size distribution (PSD) with the particle-target interaction properties able to determine the sensing efficiency.In this work, we present the characterization of colloidal tyrosine-TiO2 NP systems by flow field-flow fractionation (FlFFF) with online, UV/Vis absorption detection and offline fluorescence analysis. FlFFF eliminates the possible contribution of free tyrosine to the absorption and fluorescence properties of the NPs. FlFFF also fractionates NPs on a size basis. Particle size distribution (PSD) profiles of the fractionated NPs are then obtained by conversion of the multi-wavelength UV/Vis fractograms. Size of the fractionated NPs is finally related to fluorescence properties of the collected NPs fractions. Good correlation between the fluorescence intensity, which is proportional to the tyrosine uptake, and the FlFFF-based, NP mass-size frequency distribution finally confirms the existence of tyrosine-TiO2 NP interaction. 相似文献