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981.
Nucleophilic Additions to Coordinated 1,10‐Phenanthroline: Intramolecular,Intermolecular, Reversible,and Irreversible 下载免费PDF全文
Rebeca Arévalo Dr. M. Isabel Menéndez Dr. Ramón López Dr. Isabel Merino Dr. Lucía Riera Dr. Julio Pérez 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(50):17972-17975
KN(SiMe3)2 reacts with [Re(CO)3(phen)(PMe3)]OTf via reversible addition to the phen ligand and irreversible deprotonation of the PMe3 ligand followed by intramolecular attack to phen by the deprotonated phosphane, whereas MeLi irreversibly adds to phen. The addition of MeLi has been shown to be intermolecular, unlike previously known nucleophilic additions to pyridines. 相似文献
982.
983.
Dr. Khaleel I. Assaf Dr. Josef Holub Dr. Eduard Bernhardt Dr. Josep M. Oliva-Enrich Dr. M. Isabel Fernández Pérez Prof. Dr. Moisés Canle Dr. J. Arturo Santaballa Dr. Jindřich Fanfrlík Dr. Drahomír Hnyk Prof. Dr. Werner M. Nau 《Chemphyschem》2020,21(10):971-976
The supramolecular recognition of closo,closo-[B21H18]− by cyclodextrins (CDs) has been studied in aqueous solution by isothermal titration calorimetry and nuclear magnetic resonance spectroscopy. These solution studies follow up on previous mass-spectrometric measurements and computations, which indicated the formation and stability of CD ⋅ B21H18− complexes in the gas phase. The thermodynamic signature of solution-phase binding is exceptional, the association constant for the γ-CD complex with B21H18− reaches 1.8×106 M−1, which is on the same order of magnitude as the so far highest observed value for the complex between γ-CD and a metallacarborane. The nature of the intermolecular interaction is also examined by quantum-mechanical computational protocols. These suggest that the desolvation penalty, which is particularly low for the B21H18− anion, is the decisive factor for its high binding strength. The results further suggest that the elliptical macropolyhedral boron hydride is another example of a CD binder, whose extraordinary binding affinity is driven by the chaotropic effect, which describes the intrinsic affinity of large polarizable and weakly solvated chaotropic anions to hydrophobic cavities and surfaces in aqueous solution. 相似文献
984.
Ellen Y. Cotrina Dr. Ana Gimeno Dr. Jordi Llop Prof. Dr. Jesús Jiménez-Barbero Dr. Jordi Quintana Dr. Rafel Prohens Dr. Isabel Cardoso Dr. Gemma Arsequell 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(72):17462-17469
The protein transthyretin (TTR) modulates amyloid-β (Aβ) peptides deposition and processing and this physiological effect is further enhanced by treatment with iododiflunisal (IDIF), a small-molecule compound (SMC) with TTR tetramer stabilization properties, which behaves as chaperone of the complex. This knowledge has prompted us to design and optimize a rapid and simple high-throughput assay that relies on the ability of test compounds to form ternary soluble complexes TTR/Aβ/SMC that prevent Aβ aggregation. The method uses the shorter Aβ(12–28) sequence which is cheaper and simpler to use while retaining the aggregation properties of their parents Aβ(1–40) and Aβ(1–42). The test is carried out in 96-plate wells that are UV monitored for turbidity during 6 h. Given its reproducibility, we propose that this test can be a powerful tool for efficient screening of SMCs that act as chaperones of the TTR/Aβ interaction that may led to potential AD therapies. 相似文献
985.
986.
987.
Dr. Biplab K. Maiti Dr. Luisa B. Maia Prof. Dr. Isabel Moura Prof. Dr. José J. G. Moura 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(17):4309-4314
The nitration of tyrosine residues in proteins represents a specific footprint of the formation of reactive nitrogen species (RNS) in vivo. Here, the fusion product of orange protein (ATCUN-ORP) was used as an in vitro model system containing an amino terminal Cu(II)- and Ni(II)-binding motif (ATCUN) tag at the N-terminus and a native tyrosine residue in the metal-cofactor-binding region for the formation of 3-NO2-Tyr (3-NT). It is shown that NiII-ATCUN unusually performs nitration of tyrosine at physiological pH in the presence of the NO2−/SO32−/O2 system, which is revealed by a characteristic absorbance band at 430 nm in basic medium and 350 nm in acidic medium (fingerprint of 3-NT). Kinetics studies showed that the formation of 3-NT depends on sulfite concentration over nitrite concentration suggesting key intermediate products, identified as oxysulfur radicals, which are detected by spin-trap EPR study by using 5,5-dimethyl-1-pyrroline-N-oxide (DMPO). This study describes a new route in the formation of 3-NT, which is proposed to be linked with the sulfur metabolism pathway associated with the progression of disease occurrence in vivo. 相似文献
988.
Paula G. Saiz Naroa Iglesias Bárbara González Navarrete Maibelin Rosales Yurieth Marcela Quintero Ander Reizabal Dr. Joseba Orive Dr. Arkaitz Fidalgo Marijuan Dr. Edurne S. Larrea Dr. Ana Catarina Lopes Prof. Luis Lezama Dr. Andreina García Prof. Senentxu Lanceros-Mendez Prof. María Isabel Arriortua Dr. Roberto Fernández de Luis 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(61):13861-13872
989.
Mahmoud Benltifa Miklos De Kiss Maria Isabel Garcia-Moreno Carmen Ortiz Mellet David Gueyrard Anne Wadouachi 《Tetrahedron: Asymmetry》2009,20(15):1817-1823
We report the synthesis of spiro-sulfamidate glycosides from exo-glycals. This route is regioselective and furnishes an original class of spiro-hydantoin glycoside analogues. A biological evaluation of this family on a range of glycosidases shows that these compounds are weak but very selective inhibitors of α-glucosidase and amyloglucosidase. 相似文献
990.
Improvement of microbial cell cultures oxygenation can be achieved by the increase of total air pressure, which increases
oxygen solubility in the medium. In this work, a pressurized bioreactor was used for Yarrowia lipolytica batch cultivation under increased air pressure from 1 to 6 bar. Cell growth was strongly enhanced by the pressure rise. Fivefold
and 3.4-fold increases in the biomass production and in specific growth rate, respectively, were observed under 6 bar. The
increase of oxygen availability caused the induction of the antioxidant enzyme superoxide dismutase, which indicates that
the defensive mechanisms of the cells against oxidative stress were effective and cells could cope with increased pressure.
The pregrowth of Y. lipolytica under increased pressure conditions did not affect the lipase production ability of the cells. Moreover, the extracellular
lipase activity increased 96% using a 5-bar air pressure instead of air at 1-bar pressure during the enzyme production phase.
Thus, air pressure increase in bioreactors is an effective mean of cell mass and enzyme productivity enhancement in bioprocess
based in Y. lipolytica cultures. 相似文献