Linked Life Data

21451865

Source:http://linkedlifedata.com/resource/pubmed/id/21451865

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
10
pubmed:dateCreated
2011-4-27
pubmed:abstractText
Collision induced dissociation (CID) of sodiated peptide derivatives containing a nitrate ester functionality was used to regiospecifically generate three isomeric radicals of the model peptide Bz-Ala-Gly-OMe corresponding to radicals formed at: C(?) of the alanine residue [4+Na](+); C(?) of the glycine residue [5+Na](+); and the side chain of alanine [6+Na](+). The ion-molecule reactions of these peptide radicals were examined to model oxidative damage to peptides and to probe whether the radical sites maintain their integrity or whether they isomerise via intramolecular hydrogen atom transfer (HAT). Only [6+Na](+) is reactive towards O(2), forming the peroxyl radical [7+Na](+), which loses O(2), HO? and HO(2)? under CID. The radical ion [7 + Na](+) abstracts a hydrogen atom from 4-fluorothiophenol to form the hydroperoxide [8+Na](+), which upon CID fragments via the combined loss of HO? and CH(2)O. In contrast, all three of the isomeric sodiated radicals react with NO? and NO(2)? to form adducts. CID of the NO adducts only regenerates the radicals via NO? loss, thus providing no structural information. In contrast, CID of the NO(2) adducts gives rise to a range of product ions and the spectra are different for each of the three adducts, suggesting that the isomeric radicals [4+Na](+), [5+Na](+) and [6+Na](+) are produced as discrete species. Finally, CID of the NO(2) adducts was used to probe the rearrangement of the radicals [4+Na](+), [5+Na](+) and [6+Na](+) prior to their reaction with NO(2)?: [6 + Na](+) rearranges to a mixture of [4+Na](+) and [5+Na](+) while [5+Na](+) rearranges to [4+Na](+).
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
May
pubmed:issn
1477-0539
pubmed:author
pubmed:issnType
Electronic
pubmed:day
21
pubmed:volume
9
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
3733-45
pubmed:meshHeading
pubmed:year
2011
pubmed:articleTitle
Gas-phase ion-molecule reactions using regioselectively generated radical cations to model oxidative damage and probe radical sites in peptides.
pubmed:affiliation
ARC Centre of Excellence for Free Radical Chemistry and Biotechnology, Victoria, Australia.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't