Linked Life Data

16133205

Source:http://linkedlifedata.com/resource/pubmed/id/16133205

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
6
pubmed:dateCreated
2005-11-24
pubmed:abstractText
The enthalpic and entropic changes accompanying the reduction reaction of the six-coordinate cyanide adducts of cytochrome c, microperoxidase-11 and a few plant peroxidases were measured electrochemically. Once the compensating changes in reduction enthalpy and entropy due to solvent reorganization effects are factorized out, it is found that cyanide binding stabilizes enthalpically the ferriheme following the order: cyochrome c > peroxidase > microperoxidase-11. The effect is inversely correlated to the solvent accessibility of the heme. Comparison of the reduction thermodynamics for the cyanide adducts of cytochrome c and plant peroxidases with those for microperoxidase-11 and myoglobin, respectively, yielded an estimate of the consequences of protein encapsulation and of the anionic character of the proximal histidine on the reduction potential of the heme-cyanide group. Insertion of the heme-CN group into the folded peptide chain of cyt c induces an enthalpy-based decrease in E degrees ' of approximately 100 mV, consistent with the lower net charge of the oxidized as compared to the reduced iron center, whereas a full imidazolate character of the proximal histidine stabilizes enthalpically the ferriheme by approximately 400 mV. The latter value should be best considered as an upper limit since it also includes some solvation effects arising from the nature of the protein systems being compared.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Oct
pubmed:issn
0949-8257
pubmed:author
pubmed:issnType
Print
pubmed:volume
10
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
643-51
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
2005
pubmed:articleTitle
Axial ligation and polypeptide matrix effects on the reduction potential of heme proteins probed on their cyanide adducts.
pubmed:affiliation
Department of Chemistry and Centro SCS, University of Modena and Reggio Emilia, via Campi 183, 41100, Modena, Italy.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't