Document Detail


Dielectric spectroscopy in the GHz region on fully hydrated zwitterionic amino acids.
MedLine Citation:
PMID:  22796741     Owner:  NLM     Status:  Publisher    
Abstract/OtherAbstract:
The complex dielectric permittivity of eight different amino acids in water solutions was determined in the frequency range from 0.2 to 20 GHz at room temperature, trying to span the whole range of solubility in each case. Two relaxations were observed at room temperature in this frequency range, which can be mainly assigned to the rotation of amino acids in the aqueous environment, and the reorientational motion of water molecules, respectively. Although the amino acids have a charged (zwitterionic) nature with huge dipole moments, the tendency towards dipolar alignment seems to be very weak, over the investigated concentration ranges. For these small bio-molecules, water screens solute-solute interactions and amino acids remain typically as isolated hydrated monomers. The dielectric results were used to estimate the number of water molecules restrained by each solute molecule. Finally, the comparison between the amino acid relaxation times made it possible to discuss the relationship between rotational dynamics and the structure and hydrodynamic coupling of the amino acid studied.
Authors:
Iñigo Rodríguez-Arteche; Silvina Cerveny; Angel Alegría; Juan Colmenero
Publication Detail:
Type:  JOURNAL ARTICLE     Date:  2012-7-16
Journal Detail:
Title:  Physical chemistry chemical physics : PCCP     Volume:  -     ISSN:  1463-9084     ISO Abbreviation:  -     Publication Date:  2012 Jul 
Date Detail:
Created Date:  2012-7-16     Completed Date:  -     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  100888160     Medline TA:  Phys Chem Chem Phys     Country:  -    
Other Details:
Languages:  ENG     Pagination:  -     Citation Subset:  -    
Affiliation:
Centro de Física de Materiales - Material Physics Centre (MPC), CSIC - Universidad del País Vasco (UPV/EHU), Paseo Manuel de Lardizabal 5, 20018, San Sebastian, Spain. scerveny@ehu.es.
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