Apparent molar volumes of glycine, L-alanine, and L-serine in water + ethanol mixtures at 298.15 K

1999 ◽  
Vol 77 (3) ◽  
pp. 387-390 ◽  
Author(s):  
Xiaoling Ren ◽  
Ruisen Lin ◽  
Yaming Ni ◽  
Hanxing Zong
Keyword(s):  
Amino Acids ◽  
Hydrophobic Interactions ◽  
Pure Water ◽  
Apparent Molar Volumes ◽  
Molar Volumes ◽  
Transfer Volumes ◽  
Structure Breaking

Densities of glycine, L-alanine, and L-serine have been measured with an oscillating-tube densimeter at 298.15 K in water + ethanol (EtOH) mixtures ranging from pure water to 45% ethanol by mass. From these densities, apparent molar volumes and limiting apparent molar volumes of the three amino acids in the mixtures have been calculated. Transfer volumes are interpreted in terms of the structure-making or structure-breaking effects of water on addition of these amino acids in the mixtures. The relative contributions of hydrophilic and hydrophobic interactions in these solutions have been inferred.Key words: glycine, L-alanine, L-serine, water + ethanol mixtures, densities.

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.

Excess enthalpies and apparent molar volumes of some N-methyl substituted amino acids in aqueous solutions

1989 ◽  
Vol 18 (2) ◽  
pp. 131-142 ◽  
Author(s):  
J. F. Reading ◽  
P. A. Carlisle ◽  
G. R. Hedwig ◽  
I. D. Watson
Keyword(s):  
Amino Acids ◽  
Aqueous Solutions ◽  
Apparent Molar Volumes ◽  
Excess Enthalpies ◽  
Molar Volumes

Apparent molar volumes of some amino acids and peptides in aqueous urea solutions

Biopolymers ◽  
1983 ◽  
Vol 22 (11) ◽  
pp. 2397-2409 ◽  
Author(s):  
A. K. Mishra ◽  
K. P. Prasad ◽  
J. C. Ahluwalia
Keyword(s):  
Amino Acids ◽  
Apparent Molar Volumes ◽  
Molar Volumes ◽  
Aqueous Urea
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