Aqueous solutions containing amino acids and peptides. Part 13.—Enthalpy of dilution and osmotic coefficients of some N-acetyl amino acid amides and some N-acetyl peptide amides at 298.15 K

1982 ◽  
Vol 78 (5) ◽  
pp. 1641 ◽  
Author(s):  
G. Michael Blackburn ◽  
Terence H. Lilley ◽  
Elizabeth Walmsley
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Aqueous Solutions ◽  
Osmotic Coefficients ◽  
Enthalpy Of Dilution

Apparent molar heat capacities and volumes of some aqueous solutions of aliphatic amino acids at 288.15, 298.15, 313.15, and 328.15 K

1994 ◽  
Vol 72 (2) ◽  
pp. 362-368 ◽  
Author(s):  
Andrew W. Hakin ◽  
Michelle M. Duke ◽  
Sheri A. Klassen ◽  
Robert M. McKay ◽  
Kathryn E. Preuss
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Aqueous Solutions ◽  
Equilibrium Constants ◽  
Heat Capacities ◽  
Apparent Molar Volumes ◽  
Protein Chemistry ◽  
Standard State ◽  
Apparent Molar Heat Capacities ◽  
Molar Volumes

The thermodynamics of amino acid systems are key to the understanding of protein chemistry. We have found that many previous studies of the apparent molar volumes and heat capacities of aqueous solutions of amino acids were conducted at the standard temperature of 298.15 K. This does not allow for the fact that most biological processes occur at temperatures removed from this standard condition.In an attempt to address this imbalance we have measured densities and heat capacities for aqueous solutions of glycine, L-alanine, L-serine, and L-threonine at 288.15, 298.15, 313.15, and 328.15 K using a Picker flow microcalorimeter. Apparent molar volumes and heat capacities, and the associated standard state partial molar properties have been calculated. Constant pressure variations of revised Helgeson, Kirkham, and Flowers equations have been fitted to calculated standard state volumes and heat capacities over the temperature range 288.15 to 328.15 K. These equations may be used to estimate standard state volumes and heat capacities, and hence equilibrium constants, for aqueous amino acid systems at higher temperatures.

The volumetric and thermochemical properties of aqueous solutions of L-valine, L-leucine, and L-isoleucine at 288.15, 298.15, 313.15, and 328.15 K

1994 ◽  
Vol 72 (6) ◽  
pp. 1489-1494 ◽  
Author(s):  
Michelle M. Duke ◽  
Andrew W. Hakin ◽  
Robert M. McKay ◽  
Kathryn E. Preuss
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Aqueous Solutions ◽  
Constant Pressure ◽  
Heat Capacities ◽  
Thermochemical Properties ◽  
Acid System ◽  
Standard State ◽  
Apparent Molar Heat Capacities ◽  
Fitting Procedures

Densities and volumetric heat capacities have been measured for aqueous solutions of L-valine, L-leucine, and L-isoleucine at 288.15, 298.15, 313.15, and 328.15 K. These data have been used to calculate apparent molar volumes, [Formula: see text] and apparent molar heat capacities, [Formula: see text] which in turn have been used to obtain standard state volumes, [Formula: see text] and standard state heat capacities, [Formula: see text] for each aqueous amino acid system. Helgeson, Kirkham, and Flowers equations, for neutral organics in water, have been used to model the calculated standard state volumes and heat capacities of the amino acids as a function of temperature at constant pressure. The results of our fitting procedures may be used to predict the behaviour of [Formula: see text] and [Formula: see text] for the selected amino acid systems outside of the temperature range utilised in this investigation.

scholarly journals The Surface Composition of Amino Acid - KCl Solutions is pH-Dependent

2020 ◽  
Author(s):  
Geethanjali Gopakumar ◽  
Isaak Unger ◽  
Clara-Magdalena Saak ◽  
Gunnar Öhrwall ◽  
Arnaldo Naves de Brito ◽  
...  
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Aqueous Solutions ◽  
Photoelectron Spectroscopy ◽  
Surface Composition ◽  
Inorganic Ions ◽  
X Ray ◽  
Ph Dependent

The manuscript based on X-ray photoelectron spectroscopy on aqueous solutions containing KCl and different amino acids. Our analysis suggests that the presence of the inorganic ions at the surface of the liquid is strongly dependent on the pH of the solution and the type of amino acid.

Apparent molal heat capacities and volumes of amino acids in aqueous polyol solutions

1978 ◽  
Vol 56 (13) ◽  
pp. 1827-1831 ◽  
Author(s):  
Giuseppa DiPaola ◽  
Bernard Belleau
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Aqueous Solutions ◽  
Transfer Functions ◽  
Heat Capacities ◽  
Side Chains ◽  
Dilute Solutions ◽  
Flow Microcalorimeter ◽  
Regular Increase ◽  
Apparent Molal Heat Capacities

Densities (24 °C) and volumetric specific beats (25 °C) were measured for amino acids (0.05–0.5 m) containing apolar side chains in water, and in aqueous solutions of glycerol, mannitol, sorbitol, NaCl, urea, and Gu•HCl, with a flow densimeter and flow microcalorimeter respectively.The derived apparent molal quantifies and transfer functions of the amino acids in aqueous polyol solutions reveal no specificities which might explain the origin of the unique behavior of polyols in protein systems. However, the study did reveal a regular increase in the structure-making ability of the amino acid as the hydrophobicity of the side chains increased. This structure-making tendency was reduced significantly in dilute solutions of the higher polyols.

scholarly journals Study of the effect of temperature on the electrical conductivity of aqueous solutions of amino acids

2019 ◽  
Vol 57 (1) ◽  
pp. 91-94
Author(s):  
Vera A. Petrukhina ◽  
◽  
Pavel I. Fedorov ◽  
Tatiana A. Kirillova ◽  
Ludmila Yu. Tcareva ◽  
...  
Keyword(s):  
Experimental Data ◽  
Amino Acids ◽  
Electrical Conductivity ◽  
Amino Acid ◽  
Aqueous Solutions ◽  
Arrhenius Equation ◽  
Effect Of Temperature ◽  
Acid Solutions ◽  
Hydrogen Ions ◽  
Amino Acid Solutions

It is well-known fact that water is a universal solvent due to its physicochemical properties and dielectric constant. Therefore, the majority of substances with a crystalline structure and the structure close to it are well soluble in water due to the dissociation of molecules into ions. Amino acids are organic ampholytes – substances capable of being in ionic forms in water. The quantitative and qualitative composition of ampholytes depends on the structure and composition of amino acids and pH of solution. The interaction of amino acid ions in solution with hydrogen ions and hydroxyl leads to the formation of complex cations and anions. The presence of amino and carboxyl groups in amino acid molecules contributes to the formation of inter-ion positively and negatively charged complexes which leads to the decrease in their mobility and electrical conductivity of solutions. It is observed with increasing concentration of amino acid solutions. The conductivity of amino acid solutions is also influenced by temperature which has a non-linear relationship. We have proposed the approach based on studying the effect of temperature on the equivalent electrical conductivity at infinite dilution λ∞ and describing the experimental data λ∞(Т) by the exponential Arrhenius equation. This article studies the possibility of describing the experimental data λ∞(Т) for aqueous solutions of a number of amino acids by this equation. It is shown that the Arrhenius equation with the found activation energy values adequately describes the dependences of limiting equivalent conductivity on temperature for aqueous solutions of valine, leucine, isoleucine, threonine, lysine, methionine, phenylalanine, L-aspartic and D-aspartic acids, histidine, arginine.

Highly sensitive colorimetric detection of HgII and CuII in aqueous solutions: from amino acids toward solid platforms

The Analyst ◽  
2015 ◽  
Vol 140 (3) ◽  
pp. 744-749 ◽  
Author(s):  
Jooyoung Park ◽  
Byunggyu In ◽  
Lok Nath Neupane ◽  
Keun-Hyeung Lee
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Aqueous Solutions ◽  
Metal Ions ◽  
Colorimetric Detection ◽  
Selective Detection ◽  
Highly Sensitive ◽  
Fluorescence Change

A chemosensor (NBD-H) based on an amino acid with 7-nitro-2,1,3-benzoxadiazole was used for selective detection of HgII and CuII among 15 metal ions in aqueous solutions by a colorimetric change and fluorescence change.

scholarly journals Terahertz Absorption Properties of Two Solid Amino Acids and Their Aqueous Solutions

2021 ◽  
Vol 2021 ◽  
pp. 1-7
Author(s):  
Ping Ye ◽  
Guoyang Wang ◽  
Yizhou Yang ◽  
Qinghao Meng ◽  
Jiahui Wang ◽  
...  
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Aqueous Solutions ◽  
Density Functional ◽  
Basis Set ◽  
Molecular Vibration ◽  
Absorption Properties ◽  
Future Studies ◽  
Terahertz Absorption ◽  
The Time Domain

A new type of embedded cyclic olefin copolymer microfluidic chip was designed and combined with terahertz (THz) technology to study the effects of glycine and arginine on the THz wave absorption characteristics. This study aims to understand the interactions between solid amino acid molecules and between amino acid and water molecules and to determine the changes in their microstructure. By observing the intensity of the time domain spectra in the range of 0.2–2.6 THz, we found that, as the concentration of glycine and arginine increased, the THz transmission gradually decreased. It can be inferred that the molecular structure and quantity of different amino acids have different influence on the hydrogen bond, which affects the absorption coefficient in solution. It was also found that the terahertz technique is able to identify the solid amino acid species better, and it can also perform some species identification for liquid amino acids. These results provide a reference for future studies on the terahertz absorption properties of amino acid samples. Moreover, Gaussian16 software was used to calculate the terahertz spectra using the density functional theory, B3LYP functional, and 6-31G basis set. Additionally, Gaussian View6 video software provided the frequency values, molecular vibration modes of the theoretical absorption peaks of glycine, arginine, and its aqueous solutions in the frequency range of 0.2–2.6 THz, which offers theoretical support for future studies.

scholarly journals The Surface Composition of Amino Acid - KCl Solutions is pH-Dependent

2020 ◽  
Author(s):  
Geethanjali Gopakumar ◽  
Isaak Unger ◽  
Clara-Magdalena Saak ◽  
Gunnar Öhrwall ◽  
Arnaldo Naves de Brito ◽  
...  
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Aqueous Solutions ◽  
Photoelectron Spectroscopy ◽  
Surface Composition ◽  
Inorganic Ions ◽  
X Ray ◽  
Ph Dependent

The manuscript based on X-ray photoelectron spectroscopy on aqueous solutions containing KCl and different amino acids. Our analysis suggests that the presence of the inorganic ions at the surface of the liquid is strongly dependent on the pH of the solution and the type of amino acid.

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