Concerted transfer and transfer direction of three protons in the protonated amino-acid dimers

2006 ◽  
Vol 328 (1-3) ◽  
pp. 197-204 ◽  
Author(s):  
Hongqi Ai ◽  
Qiang Li
Keyword(s):  
Amino Acid ◽  
Protonated Amino Acid ◽  
Transfer Direction

Oxydoréduction photochimique et thermique entre le chrome(VI) et un acide α aminé (glycine, alanine, hydroxy proline et méthionine)

1986 ◽  
Vol 64 (9) ◽  
pp. 1864-1869 ◽  
Author(s):  
M. Bolte ◽  
B. Robert ◽  
J. Lemaire
Keyword(s):  
Amino Acid ◽  
Spectroscopic Studies ◽  
Quantum Yields ◽  
Charge Transfer Reaction ◽  
Acid Complex ◽  
Protonated Amino Acid ◽  
Chromium Vi ◽  
Hydroxy Proline ◽  
Amino Acid Formula ◽  
Rule Out

Photochemical and thermal oxidation that occurs between chromium(VI) and various amino acids leads quantitatively to chromium(III). Spectroscopic studies rule out the formation of a chromium(VI) – amino acid complex in the ground state. Thermal oxidoreduction involves HCrO4−, the protonated amino acid [Formula: see text] and H+ ions. Chromium(V) appears to be an intermediate species in the reaction. HCrO4− is the only absorbing compound and the photochemical chromium(VI) reduction proceeds through a reaction between [HCrO4−]* and the amino acid. Chromium(V) is the primary product of the charge transfer reaction. Reduction quantum yields are proportional to the amino acid concentration and pH independent in the HCrO4− existence range.

scholarly journals Molecular recognition of isomeric protonated amino acid esters monitored by ESI-mass spectrometry

2014 ◽  
Vol 10 ◽  
pp. 825-831 ◽  
Author(s):  
Andrea Liesenfeld ◽  
Arne Lützen
Keyword(s):  
Mass Spectrometry ◽  
Amino Acid ◽  
Isotope Effects ◽  
Amino Acid Esters ◽  
Guest Molecules ◽  
Protonated Amino Acid ◽  
Host Guest Complex ◽  
Binding Event ◽  
Esi Mass Spectrometry ◽  
Acid Esters

Two new 9,9’-spirobifluorene-derived crown ethers were prepared and used to recognise constitutionally isomeric amino acid derivatives. The performance of the receptors was evaluated by ESI-mass spectrometry using the isomer labelled guest method (ILGM). This method revealed the preferred binding of L-norleucine and L-leucine compared to L-isoleucine for both receptors. Furthermore, non-covalent isotope effects demonstrate the relevance of dispersive interactions for the overall binding event. These effects also provide hints for the relative spatial orientation of the guest molecules within the host–guest complex, and thereby prove the importance of the spirobifluorene moiety for the observed binding of the protonated amino acid esters.

scholarly journals Articular Cartilage: The Destruction of Bilayers and Deactivation of Phospholipid Molecules

2018 ◽  
Vol 1 (2) ◽  
Keyword(s):  
Articular Cartilage ◽  
Amino Acid ◽  
Functional Group ◽  
Phospholipid Membrane ◽  
Hockey Stick ◽  
Protonated Amino Acid ◽  
Glycoprotein I ◽  
Acid Functional Group

To our knowleadge the coaugulation by interacton of β2 -Glycoprotein I (β2 -GP I) with the phospholipid membrane is required to verify this hypothesis. The open hockey stick-like conformation occurs when protonated amino acid functional group (-NH3 +) β2-GP I is complexed to negatively charged phospholipids functional group (-PO4 - ) resulting in the destruction of bilayers and the deactivation of phospholipid molecules.

scholarly journals Protonated Amino Acid-Induced One-Handed Helicity of Polynorbornene Having Monoaza-18-crown-6 Pendants

2010 ◽  
Vol 43 (21) ◽  
pp. 8813-8820 ◽  
Author(s):  
Renjie Ji ◽  
Chih-Gang Chao ◽  
Yen-Chin Huang ◽  
Yi-kang Lan ◽  
Cheng-Lu Lu ◽  
...  
Keyword(s):  
Amino Acid ◽  
Protonated Amino Acid

Effect of solution acidity on the structure of amino acid-bearing uranyl compounds

2019 ◽  
Vol 107 (4) ◽  
pp. 311-325 ◽  
Author(s):  
Evgeny V. Nazarchuk ◽  
Yuri A. Ikhalaynen ◽  
Dmitri O. Charkin ◽  
Oleg I. Siidra ◽  
Vladimir G. Petrov ◽  
...  
Keyword(s):  
Amino Acid ◽  
Isonicotinic Acid ◽  
Direct Methods ◽  
Uranyl Compounds ◽  
Acidic Solutions ◽  
Protonated Amino Acid ◽  
Hydronium Ions ◽  
Organic Amines ◽  
Solution Acidity

Abstract A series of uranyl sulfates and selenates templated by protonated forms of amino acids (glycine, α- and β-alanine, threonine, nicotinic, and isonicotinic acid) has been prepared via isothermal evaporation of strongly acidic solutions. Their structures have been refined by the direct methods and can be classified as inorganic [(UO2)m(TO4)n (H2O)k] (T=S6+, Se6+) moieties combined with the protonated amino acid cations, water molecules and hydronium ions. Their overall motifs demonstrate common features with related structures templated by organic amines. The role of carboxylic acid groups depends on the nature of the corresponding amino acid. They can either link two protonated organic moieties into dimers, or contribute to hydrogen bonding between organic and inorganic parts of the structure. The ammonium ends of the amino acid cations form strong directional bonds to the oxygens of the uranyl and TO4 anions.

Determination of Water Loss Mechanism in Amine Terminous Amino Acids Using Laser Mass Spectrometry

1989 ◽  
Vol 43 (6) ◽  
pp. 1087-1092 ◽  
Author(s):  
Kenneth J. Rosnack ◽  
Kasi V. Somayajula ◽  
Andrew G. Sharkey ◽  
Nancy J. Jensen ◽  
David M. Hercules
Keyword(s):  
Mass Spectrometry ◽  
Amino Acids ◽  
Amino Acid ◽  
Water Loss ◽  
Thermal Decomposition Mechanism ◽  
Laser Mass Spectrometry ◽  
Heat Of Reaction ◽  
Loss Mechanism ◽  
Protonated Amino Acid ◽  
Lactam Ring

The water loss process in Laser Mass Spectrometry of amine terminal amino acids was studied. Water loss is proposed to occur via a thermal decomposition mechanism for a protonated amino acid forming a protonated lactam ring. The magnitude of the water loss peak is correlated with the stability of the protonated lactam ring. Semi-empirical MNDO calculations of the heat of reaction of a protonated amino acid forming a protonated lactam ring and water support the correlation. The substrate (matrix) appears to have little effect on the process; results are essentially the same with the use of different substrates and sample preparation methods.

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