Niether, Doreen ORCID: 0000-0002-8496-4215, Kriegs, Hartmut, Dhont, Jan K. G. and Wiegand, Simone ORCID: 0000-0001-6333-1956 (2018). Peptide model systems: Correlation between thermophilicity and hydrophilicity. J. Chem. Phys., 149 (4). MELVILLE: AMER INST PHYSICS. ISSN 1089-7690

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Abstract

In recent years, the response of biomolecules to a temperature gradient has been utilized to monitor reactions of biomolecules, but the underlying mechanism is not well understood due to the complexity of the multicomponent system. To identify some underlying principles, we investigate the thermal diffusion of small amide molecules in water systematically. We re-analyze previous measurements of urea and formamide and compare the results with acetamide, N-methylformamide, and N, N-dimethylformamide, amides with a lower hydrophilicity. It turns out that less hydrophilic substances do not show the typical temperature dependence of water soluble macromolecules. Analyzing temperature and concentration dependent measurements using an empirical expression originally derived for nonpolar mixtures, we find that the so-called isotope contribution depends strongly on the hydrophilicity of the solute. This can be qualitatively understood by comparing with molecular dynamic simulations of Lennard-Jones fluids. The hydrophobic/hydrophilic balance also influences the structure in the fluid and with that the thermal expansion coefficient, which correlates with the thermal diffusion coefficient. Furthermore, we observe a clear correlation of the temperature and concentration dependence of the Soret coefficient with the hydrophilicity, which can be quantitatively described by the partition coefficient log P. Published by AIP Publishing.

Item Type: Journal Article
Creators:
CreatorsEmailORCIDORCID Put Code
Niether, DoreenUNSPECIFIEDorcid.org/0000-0002-8496-4215UNSPECIFIED
Kriegs, HartmutUNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Dhont, Jan K. G.UNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Wiegand, SimoneUNSPECIFIEDorcid.org/0000-0001-6333-1956UNSPECIFIED
URN: urn:nbn:de:hbz:38-179429
DOI: 10.1063/1.5042051
Journal or Publication Title: J. Chem. Phys.
Volume: 149
Number: 4
Date: 2018
Publisher: AMER INST PHYSICS
Place of Publication: MELVILLE
ISSN: 1089-7690
Language: English
Faculty: Unspecified
Divisions: Unspecified
Subjects: no entry
Uncontrolled Keywords:
KeywordsLanguage
MOLECULAR-DYNAMICS SIMULATIONS; ETHANOL-WATER MIXTURES; THERMAL-DIFFUSION; CHARGED COLLOIDS; TEMPERATURE-DEPENDENCE; SORET COEFFICIENT; LIQUID-MIXTURES; THERMODIFFUSION; N,N-DIMETHYLFORMAMIDE; COMPRESSIBILITYMultiple languages
Chemistry, Physical; Physics, Atomic, Molecular & ChemicalMultiple languages
Refereed: Yes
URI: http://kups.ub.uni-koeln.de/id/eprint/17942

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