Linked Life Data

6362724

Source:http://linkedlifedata.com/resource/pubmed/id/6362724

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
1
pubmed:dateCreated
1984-3-20
pubmed:abstractText
The accessible tyrosines of bovine insulin were studied by the photochemically induced dynamic nuclear polarization (photo-CIDNP) method. Tyrosine 1H nuclear polarization is observed in acidic, neutral, and basic solutions at all concentrations studied, in the absence of added salts as well as in the presence of 0.05-0.1 M chloride or phosphate. At pH 2.1 in the presence of chloride, at concentrations of 640 microM and above, most of the nuclear polarization at delta 6.82 originates from one group of tyrosines. On the basis of the crystallographic model, these are assumed to be the A14 tyrosines. We explored the possibility of a genuine concentration dependence of the photo-CIDNP intensity of insulin due to aggregation. In order to discern between such effects and trivial kinetic effects traceable to the optical irradiation method, the effects of concentration changes on polarization were examined in three apparently nonassociating trypsin inhibitor proteins. In insulin, the intensity of Tyr-A 14 polarization changes slowly at concentrations above 1 mM, suggesting that these residues are similarly accessible in all association states. At insulin concentrations below 320 microM, additional tyrosine emission signals were observed. These signals are probably due to B16 and B26 tyrosines of monomers. Polarization transfer effects from Tyr-A14 are evident in the tetramer and hexamer. Enhanced absorption effects in the two histidines (B5 and B10) of the insulin monomer were observed at pH 10 in the presence of 0.1 M phosphate.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jan
pubmed:issn
0006-2960
pubmed:author
pubmed:issnType
Print
pubmed:day
3
pubmed:volume
23
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
5-10
pubmed:dateRevised
2011-11-17
pubmed:meshHeading
pubmed:year
1984
pubmed:articleTitle
Photochemically induced nuclear polarization study of the accessibility of tyrosines in insulin.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, Non-P.H.S.