Chiral recognition in aqueous solutions between enantiomeric ?-amino acids bearing substituted alkyl chains at 25�C: The peferential configuration model

1995 ◽  
Vol 24 (5) ◽  
pp. 485-497 ◽  
Author(s):  
Salvatore Andini ◽  
Giuseppina Castronuovo ◽  
Vittorio Elia ◽  
Filomena Velleca
Keyword(s):  
Amino Acids ◽  
Aqueous Solutions ◽  
Chiral Recognition ◽  
Configuration Model ◽  
Alkyl Chains

Chiral recognition in solution. Interactions of α-amino acids in concentrated aqueous solutions of urea or ethanol

1999 ◽  
Vol 77 (7) ◽  
pp. 1218-1224 ◽  
Author(s):  
Giuseppina Castronuovo ◽  
Vittorio Elia ◽  
Anna Pierro ◽  
Filomena Velleca
Keyword(s):  
Amino Acids ◽  
Aqueous Solutions ◽  
Chiral Recognition ◽  
Hydrophobic Interactions ◽  
Configuration Model ◽  
Excess Functions ◽  
Interaction Coefficients ◽  
Experimental Conditions ◽  
Concentrated Aqueous Solutions ◽  
The Difference

Enthalpies of dilution of the L and D forms of glutamine, citrulline, and phenylalanine in concentrated aqueous solutions of urea or ethanol were measured calorimetrically at 298 K. Glycine, urea, formamide, and phenol were also studied under the same experimental conditions, to get information about the behaviour of the zwitterion and of the functional group in the side chain of the cited amino acids when the concentration of the cosolvent changes. The derived pairwise enthalpic interaction coefficients for the three amino acids were rationalized according to the preferential configuration model. Indications are that, in concentrated urea, the coefficients for citrulline and glutamine are determined mainly by the interactions between the cosolvent and the hydrophilic groups in the molecule of the amino acids. For phenylalanine, coefficients are less positive than in water, because the presence of urea, which solvates preferentially the zwitterions, attenuates hydrophobic interactions between the benzene rings. In ethanol, coefficients for the three amino acid become negative or more negative than in water, because in this medium hydrophilic interactions are enhanced. Chiral recognition, namely the difference in the values of homo- and heterochiral interaction coefficients, was detected only for phenylalanine in urea. Hence, the nature of the cosolvent, influencing differently hydrophilic and hydrophobic interactions, can lead to the detection of chiral recognition also for those systems that, as phenylalanine, do not present this effect in pure water.Key words: α-amino acids, excess functions, molecular interactions, preferential configuration.

Chiral recognition in aqueous solutions at 25 °C. A calorimetric study of the interaction between enantiomeric α-amino acids of different alkyl chain length

1991 ◽  
Vol 69 (5) ◽  
pp. 794-797 ◽  
Author(s):  
Giuseppina Castronuovo ◽  
Vittorio Elia ◽  
Michela Magliulo
Keyword(s):  
Amino Acids ◽  
Aqueous Solutions ◽  
Chiral Recognition ◽  
Excess Enthalpy ◽  
Alkyl Chain ◽  
Alkyl Chain Length ◽  
Calorimetric Study ◽  
Experimental Uncertainty ◽  
Enthalpies Of Dilution

Cross-homo- and cross-heterotactic enthalpic coefficients, [Formula: see text] respectively, were determined at 25 °C, measuring the enthalpies of dilution of ternary aqueous solutions containing two different α-amino acids of the same or different chirality. Differences of about 200–300 J mol−2 kg between cross-homo- and cross-heterotactic coefficients were found, well beyond the experimental uncertainty. The role of the zwitterionic interaction, already proposed to explain the nature of chiral recognition, was strengthened. Key words: α-amino acids, excess enthalpy, chiral recognition.

Electrostriction volumes of α-amino acids from density measurements in water and in aqueous HCl and NaOH solutions at 25 °C

1993 ◽  
Vol 71 (12) ◽  
pp. 2150-2154 ◽  
Author(s):  
M. Abbate ◽  
G. Castronuovo ◽  
V. Elia ◽  
S. Puzziello
Keyword(s):  
Amino Acids ◽  
Hydrochloric Acid ◽  
Aqueous Solutions ◽  
Sodium Hydroxide ◽  
Volume Change ◽  
Pure Water ◽  
Partial Molar Volumes ◽  
Molar Volumes ◽  
Density Measurements ◽  
Alkyl Chains

The values of the limiting partial molar volumes, [Formula: see text], for some α-amino acids bearing alkyl chains, in pure water and in aqueous solutions of hydrochloric acid and sodium hydroxide, have been obtained from density measurements. From these data it is possible to determine the volume change, ΔVZW, due to the formation of the amphionic molecule from the corresponding neutral molecule.

Chiral recognition in aqueous solutions: On the role of urea in hydrophilic and hydrophobic interactions of unsubstituted ?-amino acids

1996 ◽  
Vol 25 (9) ◽  
pp. 837-848 ◽  
Author(s):  
Salvatore Andini ◽  
Giuseppina Castronuovo ◽  
Vittorio Elia ◽  
Amelia Pignone ◽  
Filomena Velleca
Keyword(s):  
Amino Acids ◽  
Aqueous Solutions ◽  
Chiral Recognition ◽  
Hydrophobic Interactions

Imaging polymers, proteins and dna in aqueous solutions with the atomic force microscope

1989 ◽  
Vol 47 ◽  
pp. 32-33
Author(s):  
S.A.C. Gould ◽  
B. Drake ◽  
C.B. Prater ◽  
A.L. Weisenhorn ◽  
S.M. Lindsay ◽  
...  
Keyword(s):  
Amino Acids ◽  
Dna Sequencing ◽  
Aqueous Solutions ◽  
Atomic Force Microscope ◽  
Piezoelectric Crystal ◽  
Atomic Force ◽  
Structure Of Molecules ◽  
Optical Lever

The atomic force microscope (AFM) is an instrument that can be used to image many samples of interest in biology and medicine. Images of polymerized amino acids, polyalanine and polyphenylalanine demonstrate the potential of the AFM for revealing the structure of molecules. Images of the protein fibrinogen which agree with TEM images demonstrate that the AFM can provide topographical data on larger molecules. Finally, images of DNA suggest the AFM may soon provide an easier and faster technique for DNA sequencing.The AFM consists of a microfabricated SiO2 triangular shaped cantilever with a diamond tip affixed at the elbow to act as a probe. The sample is mounted on a electronically driven piezoelectric crystal. It is then placed in contact with the tip and scanned. The topography of the surface causes minute deflections in the 100 μm long cantilever which are detected using an optical lever.

Chiral Recognition and Separation of Amino Acids by Means of a Copper(II) Complex of Histamine Monofunctionalized .beta.-Cyclodextrin

1994 ◽  
Vol 116 (22) ◽  
pp. 10267-10274 ◽  
Author(s):  
Roberto Corradini ◽  
Arnaldo Dossena ◽  
Giuseppe Impellizzeri ◽  
Giuseppe Maccarrone ◽  
Rosangela Marchelli ◽  
...  
Keyword(s):  
Amino Acids ◽  
Chiral Recognition ◽  
Beta Cyclodextrin

The Use of Chiral Recognition in a Bioorganic System for Determination of Optical Purity of Labelled Amino Acids

2010 ◽  
Vol 91 (5) ◽  
pp. 491-491
Author(s):  
G. Bergson ◽  
C. Halldin ◽  
H. Lundqvist ◽  
B. Långström ◽  
M. Malmqvist
Keyword(s):  
Amino Acids ◽  
Chiral Recognition ◽  
Optical Purity

ChemInform Abstract: HOST-GUEST COMPLEXATION. 22. RECIPROCAL CHIRAL RECOGNITION BETWEEN AMINO ACIDS AND DILOCULAR SYSTEMS

1980 ◽  
Vol 11 (25) ◽  
Author(s):  
S. S. PEACOCK ◽  
D. M. WALBA ◽  
F. C. A. GAETA ◽  
R. C. HELGESON ◽  
D. J. CRAM
Keyword(s):  
Amino Acids ◽  
Chiral Recognition
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