Linked Life Data

18068661

Source:http://linkedlifedata.com/resource/pubmed/id/18068661

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
2
pubmed:dateCreated
2008-2-4
pubmed:abstractText
The heat capacity changes for interaction of human serum albumin (HSA) and a cationic surfactant-cetylpyridinium chloride (CPC), were studied at conditions close to physiological (50mM HEPES or phosphate buffer, pH 7.4 and 160mM NaCl) carrying out isothermal calorimetric titrations (ITC) at various temperatures (20-40 degrees C). ITC measurements indicated that the small endothermic changes associated with CPC demicellization were temperature independent at these conditions. Surprisingly, important enthalpy changes associated with binding of CPC to HSA were exothermic and temperature independent at lower concentrations (below 0.022mM) of CPC and endothermic and temperature dependent at higher concentrations of CPC. The values of heat capacity changes were obtained for each studied concentration of CPC from the plot of enthalpy changes vs temperature. The obtained results demonstrate the temperature independence of heat capacity changes at entire range of studied CPC concentrations. Both enthalpograms and heat capacity curves indicate the two-step mechanism of HSA folding changes due to its interactions with CPC. The first step corresponds to transition from native state to partially unfolded state and the second to unfolding and to the loss of tertiary structure. The analysis of the results indicates that predominant cooperative unfolding occurs at CPC/HSA molar ratio region between 25 and 30. Such information could not be extracted from thermograms and describes the role of heat capacity as a major thermodynamic quantity giving insight on physical, mechanistic and even atomic-level into how HSA may unfold and interact with CPC. The effect of CPC binding on HSA intrinsic fluorescence, UV-Vis and CD spectra were also examined. Hence, the analysis of spectral data confirms the ITC results about the biphasic mechanism of HSA folding changes induced by CPC. The CD measurement also represents the conservation of considerable secondary structure of HSA due to interaction with CPC.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Feb
pubmed:issn
1096-0384
pubmed:author
pubmed:issnType
Electronic
pubmed:day
15
pubmed:volume
470
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
103-10
pubmed:meshHeading
pubmed:year
2008
pubmed:articleTitle
Energetics of the interactions of human serum albumin with cationic surfactant.
pubmed:affiliation
Laboratory of Biophysical Chemistry, Department of Chemistry, University of Isfahan, Isfahan, 81746-73441, Islamic Republic of Iran. bordbar@chem.ui.ac.ir
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't