Amino acid sequence determination of phosphoenkephalins using liquid secondary ionization mass spectrometry.
Rapid Commun Mass Spectrom
; 9(12): 1148-54, 1995.
Article
in En
| MEDLINE
| ID: mdl-7579627
ABSTRACT
Liquid secondary ionization mass spectrometry (LSIMS) operating in the positive- and negative-ion modes was used to study fragmentation profiles and to obtain the amino acid sequences of a set of seven phosphoenkephalin peptides. The use of glycerol as the liquid matrix led to increase in fragmentation of phosphopeptides. The prominent amino acid sequence-determining ions in the positive-ion mode are y-type C-terminal ions; the N-terminal sequence-specific ions are observed sporadically. The most dominant ions in those mass spectra, however, are the immonium ions and a few low-mass side-chain cleavage products. The mass spectra in the negative-ion mode are more information-rich, and provide data complementary to that from the positive-ion mode. The phosphate group marker ions, m/z 79 (PO-3) and 97 (H2PO-4), are prominent and both N- and C-termini sequence ions are formed with equal facility in this mode of analysis. Both positive- and negative-ion mass spectral data are useful in determining the amino acid sequence of all the seven phosphoenkephalins. Thus, LSIMS alone can be a viable option to the tandem mass spectrometry approach when sufficient quantities (> 50 nmol) of phosphopeptides are available.
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Collection:
01-internacional
Database:
MEDLINE
Main subject:
Phosphopeptides
/
Enkephalins
Language:
En
Journal:
Rapid Commun Mass Spectrom
Year:
1995
Document type:
Article
Affiliation country:
United States