Linked Life Data

8130342

Source:http://linkedlifedata.com/resource/pubmed/id/8130342

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
1
pubmed:dateCreated
1994-4-18
pubmed:abstractText
Differential scanning calorimetric (DSC) studies of the glassy states of as-received and hydrated lysozyme, hemoglobin, and myoglobin powders, with water contents of < or = 0.25, < or = 0.30, and < or = 0.29 g/g of protein, show that their heat capacity slowly increases with increasing temperature, without showing an abrupt increase characteristic of glass-->liquid transition. Annealing (also referred to as physical aging) of the hydrated proteins causes their DSC scans to show an endothermic region, similar to an overshoot, immediately above the annealing temperature. This annealing effect appears at all temperatures between approximately 150 and 300 K. The area under these peaks increases with increasing annealing time at a fixed temperature. The effects are attributed to the presence of a large number of local structures in which macromolecular segments diffuse at different time scales over a broad range. The lowest time scale corresponds to the > N-H and -O-H group motions which become kinetically unfrozen at approximately 150-170 K on heating at a rate of 30 K min-1 and which have a relaxation time of 5-10 s in this temperature range. The annealing effects confirm that the individual glass transition of the relaxing local regions is spread over a temperature range up to the denaturation temperature region of the proteins. The interpretation is supported by simulation of DSC scans in which the distribution of relaxation times is assumed to be exceptionally broad and in which annealing done at several temperatures over a wide range produces endothermic effects (or regions of DSC scans) qualitatively similar to those observed for the hydrated proteins.
pubmed:commentsCorrections
http://linkedlifedata.com/resource/pubmed/commentcorrection/8130342-13637993, http://linkedlifedata.com/resource/pubmed/commentcorrection/8130342-1463572, http://linkedlifedata.com/resource/pubmed/commentcorrection/8130342-2036357, http://linkedlifedata.com/resource/pubmed/commentcorrection/8130342-2069077, http://linkedlifedata.com/resource/pubmed/commentcorrection/8130342-2664856, http://linkedlifedata.com/resource/pubmed/commentcorrection/8130342-2918910, http://linkedlifedata.com/resource/pubmed/commentcorrection/8130342-3016460, http://linkedlifedata.com/resource/pubmed/commentcorrection/8130342-3233305, http://linkedlifedata.com/resource/pubmed/commentcorrection/8130342-3736421, http://linkedlifedata.com/resource/pubmed/commentcorrection/8130342-3736423, http://linkedlifedata.com/resource/pubmed/commentcorrection/8130342-3741983, http://linkedlifedata.com/resource/pubmed/commentcorrection/8130342-3783710, http://linkedlifedata.com/resource/pubmed/commentcorrection/8130342-4371481, http://linkedlifedata.com/resource/pubmed/commentcorrection/8130342-4598824, http://linkedlifedata.com/resource/pubmed/commentcorrection/8130342-672648, http://linkedlifedata.com/resource/pubmed/commentcorrection/8130342-672650
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jan
pubmed:issn
0006-3495
pubmed:author
pubmed:issnType
Print
pubmed:volume
66
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
249-58
pubmed:dateRevised
2010-9-13
pubmed:meshHeading
pubmed:year
1994
pubmed:articleTitle
Calorimetric studies of the kinetic unfreezing of molecular motions in hydrated lysozyme, hemoglobin, and myoglobin.
pubmed:affiliation
Institut für Allgemeine, Anorganische und Theoretische Chemie, Universität Innsbruck, Austria.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't