Document Detail


Formation of [b3 - 1 + cat]+ ions from metal-cationized tetrapeptides containing beta-alanine, gamma-aminobutyric acid or epsilon-aminocaproic acid residues.
MedLine Citation:
PMID:  18449851     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
The presence and position of a single beta-alanine (betaA), gamma-aminobutyric acid (gammaABu) or epsilon-aminocaproic acid (Cap) residue has been shown to have a significant influence on the formation of b(n)+ and y(n)+ product ions from a series of model, protonated peptides. In this study, we examined the effect of the same residues on the formation of analogous [b3 - 1 + cat]+ products from metal (Li+, Na+ and Ag+)-cationized peptides. The larger amino acids suppress formation of b3+ from protonated peptides with general sequence AAXG (where X = beta-alanine, gamma-aminobutyric acid or epsilon-aminocaproic acid), presumably because of the prohibitive effect of larger cyclic intermediates in the 'oxazolone' pathway. However, abundant [b3 - 1 + cat]+ products are generated from metal-cationized versions of AAXG. Using a group of deuterium-labeled and exchanged peptides, we found that formation of [b3 - 1 + cat]+ involves transfer of either amide or alpha-carbon position H atoms, and the tendency to transfer the atom from the alpha-carbon position increases with the size of the amino acid in position X. To account for the transfer of the H atom, a mechanism involving formation of a ketene product as [b3 - 1 + cat]+ is proposed.
Authors:
Sandra M Osburn; Sila O Ochola; Erach R Talaty; Michael J Van Stipdonk
Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't; Research Support, U.S. Gov't, Non-P.H.S.    
Journal Detail:
Title:  Journal of mass spectrometry : JMS     Volume:  43     ISSN:  1076-5174     ISO Abbreviation:  J Mass Spectrom     Publication Date:  2008 Nov 
Date Detail:
Created Date:  2008-10-29     Completed Date:  2009-01-08     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  9504818     Medline TA:  J Mass Spectrom     Country:  England    
Other Details:
Languages:  eng     Pagination:  1458-69     Citation Subset:  IM    
Affiliation:
Department of Chemistry, Wichita State University, 1845 Fairmount, Wichita, KS 67260-0051, USA.
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MeSH Terms
Descriptor/Qualifier:
6-Aminocaproic Acid / chemistry*
Cations
Ions
Metals / chemistry*
Peptides / chemistry*
Spectrometry, Mass, Electrospray Ionization / methods*
beta-Alanine / chemistry*
gamma-Aminobutyric Acid / chemistry*
Chemical
Reg. No./Substance:
0/Cations; 0/Ions; 0/Metals; 0/Peptides; 107-95-9/beta-Alanine; 56-12-2/gamma-Aminobutyric Acid; 60-32-2/6-Aminocaproic Acid

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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