Valence parity renders z(*)-type ions chemically distinct.
J Am Chem Soc
; 130(20): 6388-94, 2008 May 21.
Article
em En
| MEDLINE
| ID: mdl-18444621
ABSTRACT
Here we report that the odd electron z (*) -type ions formed by the electron-based peptide dissociation methods (electron capture or transfer, ECD or ETD) have distinctive chemical compositions from other common product ion types. Specifically, b-, c-, and y-type ions have an odd number of atoms with an odd valence (e.g., N and H), while z (*)-type ions contain an even number of atoms with an odd valence. This tenet, referred to as the valence parity rule, mandates that no c-type ion shall have the same chemical composition, and by extension mass, as a z (*) -type ion. By experiment we demonstrate that nearly half of all observed c- and z (*) -type product ions resulting from 226 ETD product ion spectra can be assigned to a single, correct, chemical composition and ion type by simple inspection of the m/ z peaks. The assignments provide (1) a platform to directly determine amino acid composition, (2) an input for database search algorithms, or (3) a basis for de novo sequence analysis.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Peptídeos
/
Espectrometria de Massas em Tandem
Idioma:
En
Ano de publicação:
2008
Tipo de documento:
Article