Linked Life Data

8051140

Source:http://linkedlifedata.com/resource/pubmed/id/8051140

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
32
pubmed:dateCreated
1994-9-6
pubmed:abstractText
Resonance Raman spectra of the ferric homodimeric hemoglobin from Scapharca inaequivalvis have been measured over the pH range 5.8-8.3 in buffers of ionic strengths 0.01 and 0.1 M to determine the spin and coordination state of the iron atom. Three species contribute to the spectra: a low spin hexacoordinate, a high spin pentacoordinate, and a high spin hexacoordinate component. Optical absorption and EPR spectra measured under the same conditions allowed the identification of the ligands in the sixth coordination position, namely the distal histidine in the low spin derivative and a water molecule in the high spin one. The relative concentrations of these three species depend on pH in an unusual way. Thus, the aquomet derivative is present over the whole pH range, albeit in small amounts as most of the hemoglobin converts to the low spin hemichrome at acid pH values and to the pentacoordinate derivative at neutral and slightly alkaline ones. The formation of a pentacoordinate heme as the pH is increased has not been reported previously for other myoglobins and hemoglobins. Low ionic strength and high protein concentration favor the formation of the high spin pentacoordinate species, while at high ionic strength and low protein concentration the low spin hexacoordinate species prevails. Ionization of the iron-bound water molecule occurs at pH > or = 9.3; accordingly, signals from the hydroxyl derivative were not observed in the Raman spectra over the pH range studied.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Aug
pubmed:issn
0021-9258
pubmed:author
pubmed:issnType
Print
pubmed:day
12
pubmed:volume
269
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
20437-40
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
1994
pubmed:articleTitle
Structural characterization of oxidized dimeric Scapharca inaequivalvis hemoglobin by resonance Raman spectroscopy.
pubmed:affiliation
Department of Biochemical Sciences A. Rossi Fanelli, University La Sapienza, Rome, Italy.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't