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排序方式: 共有1626条查询结果,搜索用时 15 毫秒
991.
Lucía Tapia Naiara Solozabal Dr. Jordi Solà Dr. Yolanda Pérez Prof. Dr. W. Todd Miller Dr. Ignacio Alfonso 《Chemistry (Weinheim an der Bergstrasse, Germany)》2021,27(37):9542-9549
The selective recognition of tyrosine residues in peptides is an appealing approach to inhibiting their tyrosine kinase (TK)-mediated phosphorylation. Herein, we describe pseudopeptidic cages that efficiently protect substrates from the action of the Src TK enzyme, precluding the corresponding Tyr phosphorylation. Fluorescence emission titrations show that the most efficient cage inhibitors strongly bind the peptide substrates with a very good correlation between the binding constant and the inhibitory potency. Structural insights and additional control experiments further support the proposed mechanism of selective supramolecular protection of the substrates. Moreover, the approach also works in a completely different kinase-substrate system. These results illustrate the potential of supramolecular complexes for the efficient and selective modulation of TK signaling. 相似文献
992.
993.
Marisol Correa-Ascencio Elizabeth K. Galván-Miranda Verónica García-Montalvo Roberto Cao Raymundo Cea-Olivares Omar Jiménez-Sandoval Irma Lucía Vera-Estrada 《Surface and interface analysis : SIA》2020,52(11):707-716
The interaction of the 4,5-bis(diphenylthiophosphinoyl)-1,2,3-triazolate (SPTz−) with different gold surfaces was investigated (nanoparticles, an electrode, and flat sheets). Studies on binding affinity of this dithiophosphin-triazolate on a gold electrode were performed by cyclic voltammetry (CV). Voltammograms exhibit two reductive desorption and only one oxidative readsorption, indicating that once reabsorbed, the molecule achieves a unique conformation. The morphology and average size of modified gold nanoparticles were studied by transmission electron microscopy (TEM) (av. diameter of 5.9 ± 1.8 nm). Further characterization was made by UV-visible (UV-vis) spectroscopy showing surface plasmon resonance (SPR) at about 580 nm. The bonding configurations of SPTz− on gold have also been investigated by comparing the FT-IR and FT-Raman spectra. The 31P{1H} NMR spectrum of capped nanoparticles exhibited two sharp signals at 30.3 and 29.6 ppm and a very broad signal at 72.7 ppm. X-ray photoelectron spectroscopy (XPS) showed SPTz− can accomplish a strong interaction with gold nanoparticles through bonds involving a sulfur atom and a nitrogen from the triazole ring with a free terminal PS group, forming self-assembled monolayers (SAM). This may allow subsequent functionalization through free S/N atoms of the formed SAMs. The SPTz− packing led to a reduction in packing density that permits large spaces between adsorbed headgroups and the inclusion of carbon and oxygen impurities from small molecules; nevertheless, oxidized sulfur or nitrogen species were not detected, indicating the chemical stability of the obtained SAMs. 相似文献
994.
995.
Evaluation of the enantioselective binding of imazalil to human serum albumin by capillary electrophoresis
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Lucía Asensi‐Bernardi Yolanda Martín‐Biosca Laura Escuder‐Gilabert Salvador Sagrado María José Medina‐Hernández 《Biomedical chromatography : BMC》2015,29(11):1637-1642
In this work, a methodology for the evaluation of enantioselective binding of imazalil (IMA) enantiomers to human serum albumin (HSA) that does not require the separation of free and bound to HSA fractions is developed. This methodology comprises the incubation of IMA–HSA designed mixtures for 30 min directly in the capillary electrophoresis system and the subsequent direct injection and chiral separation of IMA employing highly sulfated β‐cyclodextrin as chiral selector and the complete filling technique. Two mathematical approaches were used to estimate apparent affinity constants (K1), protein binding and enantioselectivity (ES) for both enantiomers of IMA. Moderate enantioselective binding of IMA enantiomers to HSA (ES = 2.0) was shown by the 1:1 stoichiometry and log K1 values of 3.4 ± 0.4 and 3.1 ± 0.3 for the first and second eluted enantiomers, respectively. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
996.
Mayya Sundukova Efthymia Prifti Annalisa Bucci Kseniia Kirillova Joana Serrao Luc Reymond Miwa Umebayashi Ruud Hovius Howard Riezman Kai Johnsson Paul A. Heppenstall 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(8):2363-2366
Optical monitoring of neuronal voltage using fluorescent indicators is a powerful approach for the interrogation of the cellular and molecular logic of the nervous system. Herein, a semisynthetic tethered voltage indicator (STeVI1) based upon nile red is described that displays voltage sensitivity when genetically targeted to neuronal membranes. This environmentally sensitive probe allows for wash‐free imaging and faithfully detects supra‐ and sub‐threshold activity in neurons. 相似文献
997.
998.
The occurrence of formaldehyde in sap and wood tissue of treated and untreated maple sugar trees was investigated using GC/MS. Samples were collected at different periods of the 2009 season and at different locations in Quebec, Canada. The natural concentration of formaldehyde found in untreated samples varied according to periods and locations and ranged from below the LOQ to 1.82 mg/kg for sap samples and from 2.39 to 8.92 mg/kg of fresh tissue for wood samples. Late season samples tended to have higher concentrations of formaldehyde. Samples of sap and wood tissue from tapholes treated with solutions of formaldehyde showed increased concentrations of formaldehyde for many days after treatment and were clearly distinct from untreated samples. These results will be useful to elaborate new inspection procedures for sugarbushes to control the illegal use of formaldehyde. 相似文献
999.
Recent increases in energy demands as a consequence of population growth and industrialization, and pollution caused during the extraction and combustion of fossil fuel sources have driven the development of new energy sources that do not cause pollution and are inexpensive and renewable. Consequently, it is necessary to develop alternative ways of generating biofuels that put less pressure on agricultural lands and water supplies, and ensure ecosystems conservation. In order to achieve the proposed goals related to energetic coverage and independence, several approaches have been developed, including biodiesel production using vegetal oils as feedstock. The aim of the current research project was to apply a nonconventional bioprocess for in vitro biomass and oil production of Jatropha curcas, for assessing different J. curcas varieties, where seed tissue was isolated and used for callus induction. Once friable callus was obtained, cell suspension cultures were established. The cell viability, fatty acid content, and characteristics were used to select the most promising cell line according to its fatty acid profile and ability to grow and develop under in vitro conditions. Oil produced by cell suspension culture of the Jatropha varieties studied was extracted and characterized by GC/MS. Differences encountered among Jatropha varieties were related to their fatty acid profiles, oil content (% on dry basis), and cell viability measurements (%). 相似文献
1000.