Linked Life Data

20449038

Source:http://linkedlifedata.com/resource/pubmed/id/20449038

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
39
pubmed:dateCreated
2010-5-7
pubmed:abstractText
Hydration and preferential hydration of macromolecules are two distinct properties of their multicomponent aqueous solutions. We have experimentally investigated ternary diffusion in a macromolecule-osmolyte-water system in order to characterize and compare these two independent quantities and to experimentally establish their role on the phenomenon of coupled diffusion. Specifically, we report the four diffusion coefficients for the poly(ethylene glycol)-di(ethylene glycol)-water system at 25 degrees C using Rayleigh interferometry. In this work, the molecular weight of poly(ethylene glycol) (PEG) is 200-fold higher than that of di(ethylene glycol) (DEG). This ratio is comparable to that between proteins and low molecular-weight osmolytes. This system has been selected because both solutes are neutral hydrated species with similar chemical properties and very different size. Hence, the observed behavior of coupled diffusion can be directly related to solute hydration and size ratio and is not complicated by other factors such as ionic interactions usually encountered in protein systems. Using our multicomponent diffusion coefficients, we have found that PEG hydration is slightly smaller than its preferential hydration. The observed difference can be attributed to PEG-DEG excluded-volume interactions. Our experimental results also enable us to reveal that Onsager cross-transport coefficients are large and negative. This implies that this transport coefficient should not be neglected in multicomponent-diffusion theoretical models even when ionic interactions or chemical association between the solute species are absent. This work provides the basis for understanding coupled diffusion in more complex aqueous systems such as those containing charged proteins or nucleic acids in the presence of salts or osmolytes.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Oct
pubmed:issn
1463-9084
pubmed:author
pubmed:issnType
Electronic
pubmed:day
21
pubmed:volume
11
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
8923-32
pubmed:meshHeading
pubmed:year
2009
pubmed:articleTitle
Macromolecular hydration compared with preferential hydration and their role on macromolecule-osmolyte coupled diffusion.
pubmed:affiliation
Department of Chemistry, Texas Christian University, Box 298860, Fort Worth, Texas 76129, USA.
pubmed:publicationType
Journal Article, Comparative Study, Research Support, Non-U.S. Gov't