Linked Life Data

891540

Source:http://linkedlifedata.com/resource/pubmed/id/891540

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
2
pubmed:dateCreated
1977-10-20
pubmed:abstractText
Hemoglobin and apohemoglobin bind heptoglobin in the same molar ratio. Structural studies on haptoglobin-hemoglobin complex do not suggest any important structural changes in either protein upon binding. However, when apohemoglobin is bound to haptoglobin, a marked reduction in secondary structure, attributed to unfolding of globin chains, has been observed. Here we describe some properties of the haptoglobin-apohemoglobin (Hp-apoHb) complex, prepared by isoelectric focusing in the presence of an excess of haptoglobin. This complex does not exhibit the irreversibility of complexes obtained with hemoglobin in identical experimental conditions. The 'freezing' of the conformation of apohemoglobin upon binding to haptoglobin has been studied by fluorescence quenching experiments carried out in the presence of 8 M acrylamide. Changes in conformation of haptoglobin upon binding to apohemoglobin have been detected by titration of the exposed tryptophans using N-bromosuccinimide. Comparison of the additivity of exposed tryptophans in the complexes reveal that two tryptophans become inaccessible in the complex formation of haptoglobin with hemoglobin but not with apohemoglobin. These tryptophans, probably located on the alpha1beta2 contact interface of hemoglobin, have been tentatively identified as Trp-C3(37)beta.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jul
pubmed:issn
0014-2956
pubmed:author
pubmed:issnType
Print
pubmed:day
15
pubmed:volume
77
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
367-73
pubmed:dateRevised
2007-7-23
pubmed:meshHeading
pubmed:year
1977
pubmed:articleTitle
Studies on hemoglobin tryptophanyl contact residues in the haptoglobin-hemoglobin complex.
pubmed:publicationType
Journal Article