نتایج جستجو برای: isomerization

تعداد نتایج: 5525  

Journal: :The Journal of chemical physics 2005
Jasper R Clarkson Esteban Baquero Timothy S Zwier

The methods of stimulated emission pumping-hole-filling spectroscopy (SEP-HFS) and population transfer spectroscopy (SEP-PTS) were used to place direct experimental bounds on the energetic barriers to conformational isomerization in 3-indole-propionic acid (IPA) and its water-containing complex. By contrast with tryptamine (Paper I), IPA has only two conformations with significant population in...

Journal: :Neuron 2009
Sangwoo Shim Joseph P. Yuan Ju Young Kim Weizhong Zeng Guo Huang Aleksandr Milshteyn Dorothee Kern Shmuel Muallem Guo-li Ming Paul F. Worley

Immunophilins, including FK506-binding proteins (FKBPs), are protein chaperones with peptidyl-prolyl isomerase (PPIase) activity. Initially identified as pharmacological receptors for immunosuppressants to regulate immune responses via isomerase-independent mechanisms, FKBPs are most highly expressed in the nervous system, where their physiological function as isomerases remains unknown. We dem...

Journal: :Proteins 2004
Atsushi Yamada Takakazu Ishikura Takahisa Yamato

We show the unexpectedly important role of the protein environment in the primary step of the photoreaction of the yellow protein after light illumination. The driving force of the trans-to-cis isomerization reaction was analyzed by a computational method. The force was separated into two different components: the term due to the protein-chromophore interaction and the intrinsic term of the chr...

2013
Neeraj Rai Stavros Caratzoulas Dionisios G. Vlachos

Density functional calculations are used to elucidate the role of the silanol group adjacent to the active site Sn metal center of the Sn-BEA zeolite in the isomerization and epimerization of glucose. We find that the silanol group plays an important role in the isomerization reaction, wherein hydride transfer and subsequent proton transfer occur in a single step with a lower energy of activati...

Journal: :Nanoscale 2015
Jie S Zhu Young-Seok Shon

Unsupported thiolate-capped palladium nanoparticle catalysts are found to be highly substrate-selective for alkene hydrogenation and isomerization. Steric and poisoning effects from thiolate ligands on the nanoparticle surface control reactivity and selectivity by influencing alkene adsorption and directing either di-σ or mono-σ bond formation. The presence of overlapping p orbitals and α proto...

Journal: :Journal of bacteriology 2003
Angelika von Wallbrunn Hans Hermann Richnow Grit Neumann Friedhelm Meinhardt Hermann J Heipieper

We studied the pattern of the cis-trans isomerization of unsaturated fatty acids in cells of Pseudomonas putida S12 grown in a medium supplemented with oleic acid which was deuterated at both of the C atoms of its double bond. Direct evidence that isomerization does not include a transient saturation of the double bond was obtained. In addition, analysis of the amino acid sequences of the seven...

Journal: :Organic letters 1999
C Cox T Lectka

[reaction: see text] We report for the first time that stoichiometric and even catalytic quantities of weak acids in aqueous solution can very efficiently catalyze amide isomerization in a carefully designed system in which a proton donor is situated so that intramolecular hydrogen bonding to the amide nitrogen is highly favored. Our results provide the first experimental verification that hydr...

2016
Michael J. Butler Andrew J. P. White Mark R. Crimmin

Reaction of a zinc/zirconium heterobimetallic complex with 1,5-cyclooctadiene (1,5-COD) results in slow isomerization to 1,3-cyclooctadiene (1,3-COD), along with the formation of a new complex that includes a cyclooctyne ligand bridging two metal centers. While analogous magnesium/zirconium and aluminum/zirconium heterobimetallic complexes are competent for the catalytic isomerization of 1,5-CO...

Journal: :Proceedings of the National Academy of Sciences of the United States of America 2004
Ashish B Patel Evan Crocker Markus Eilers Amiram Hirshfeld Mordechai Sheves Steven O Smith

Activation of the visual pigment rhodopsin is caused by 11-cis to -trans isomerization of its retinal chromophore. High-resolution solid-state NMR measurements on both rhodopsin and the metarhodopsin II intermediate show how retinal isomerization disrupts helix interactions that lock the receptor off in the dark. We made 2D dipolar-assisted rotational resonance NMR measurements between (13)C-la...

2014
Hermann A. Wegner Luca Schweighauser Daniel Häussinger Markus Neuburger

PAPER Hermann A. Wegner et al. Symmetry as a new element to control molecular switches a The isomerization properties of an azocarbazole macrocycle in solution were investigated utilizing NMR spectroscopy with in situ irradiation in combination with DFT calculations. It was demonstrated that the position of azo units in a rigid macrocyclic system influences the photoisomerization pathway even i...

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