Results 171 to 180 of about 230,876 (232)
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Biochemistry, 1997
The basicities of the diad H57-D102 at N(epsilon)2 in the tetrahedral complexes of chymotrypsin with the peptidyl trifluoromethyl ketones (TFK) N-acetyl-L-Leu-DL-Phe-CF3 and N-acetyl-DL-Phe-CF3 have been studied by 1H-NMR. The protons bridging His 57 and Asp 102 in these complexes are engaged in low-barrier hydrogen bonds (LBHBs).
C. Cassidy, Jing Lin, Perry A. Frey
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The basicities of the diad H57-D102 at N(epsilon)2 in the tetrahedral complexes of chymotrypsin with the peptidyl trifluoromethyl ketones (TFK) N-acetyl-L-Leu-DL-Phe-CF3 and N-acetyl-DL-Phe-CF3 have been studied by 1H-NMR. The protons bridging His 57 and Asp 102 in these complexes are engaged in low-barrier hydrogen bonds (LBHBs).
C. Cassidy, Jing Lin, Perry A. Frey
semanticscholar +4 more sources
A Novel Engineered Subtilisin BPN‘ Lacking a Low-Barrier Hydrogen Bond in the Catalytic Triad
Biochemistry, 2001 Jennifer Stratton +2 more
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The crucial role of water in shaping low-barrier hydrogen bonds
Physical Chemistry Chemical Physics, 2016Low-barrier hydrogen bonds (LBHBs) are key components in a range of chemical processes, often appearing in metal-mediated catalytic applications.
Timothy M. Korter, Michael T. Ruggiero
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Evidence of a Low-Barrier Hydrogen Bond in the Tryptophan Synthase Catalytic Mechanism
Biochemistry, 1996In the absence of other substrates, L-Ser reacts rapidly with the tryptophan synthase alpha 2 beta 2 bienzyme from Salmonella typhimurium at pH 7.8 and 25 degrees C to give an equilibrating mixture of species dominated by comparable amounts of the L-Ser external aldimine Schiff base, E(Aex1), and the alpha-aminoacrylate Schiff base, E(A-A).
Michael F. Dunn +2 more
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Are Short, Low-Barrier Hydrogen Bonds Unusually Strong?
Accounts of Chemical Research, 2010In a symmetric hydrogen bond (H-bond), the hydrogen atom is perfectly centered between the two donor atoms. The energy diagram for hydrogen motion is thus a single-well potential, rather than the double-well potential of a more typical H-bond, in which the hydrogen is covalently bonded to one atom and H-bonded to the other.
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ChemInform, 2001 AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
Dexter B. Northrop
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Angewandte Chemie International Edition, 2017 AbstractWhile NMR and IR spectroscopic signatures and structural characteristics of low‐barrier hydrogen bond (LBHB) formation are well documented in the literature, direct measurement of the LBHB energy is difficult. Here, we show that solid‐state 17O NMR spectroscopy can provide unique information about the energy required to break a LBHB.
Jiasheng Lu +5 more
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Low barrier hydrogen bonds within salicylate mono-anions
Tetrahedron, 2001Abstract Progressive incorporation of electron-withdrawing substituents into the aromatic ring of salicylic acid selectively acidifies the ArOH group, until the intrinsic pKa values of the ArOH and ArCO2H groups become matched, as in the case of 3-chloro-5-nitrosalicylic acid.
Layne A. Morsch, William L. Mock
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Low barrier hydrogen bonds in sterically modified Schiff bases
Journal of the Chemical Society, Perkin Transactions 2, 2002Five derivatives of an ortho-hydroxy Schiff base (2-(N-alkyl-α-iminoethyl)phenols) with very short intramolecular hydrogen bonds (dO(H)⋯N ≤ 2.500 A) were synthesised. The crystal structures were determined. The steric repulsion of the substituted methyl group results in an unusual strengthening of the hydrogen bonds, decreasing the barrier for the ...
Aleksander Koll +2 more
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