[M + Fe - 5H]2- peptide ion composition verified by Fourier transform mass spectrometry accurate mass and tandem mass spectrometry analyses.
Previously, the unusual ion composition [M + Fe - 5H]2- had been proposed as the major species observed when a gamma-carboxy glutamate-containing glyco-peptide was analyzed with electrospray ionization in the negative ionization mode. The sequence assignment of this highly post-translationally modified peptide was based on the mass analysis using a quadrupole ion trap together with information from both Edman and DNA sequencing. Because there was little precedent for the loss of five protons from a ferric cationized peptide, we utilized Fourier transform mass spectrometry accurate mass and tandem mass spectrometry analyses to verify the peptide ion composition.
Craig
A G
AG
Clayton Foundation Laboratories for Peptide Biology, Salk Institute, La Jolla, California 92186-5800, USA. craig@salk.edu
Speir
J P
JP
Rosamilia
S
S
Fursey
V
V
Lirazan
M B
MB
D000478:Alkylation; D000596:Amino Acids / Q000032:analysis; D005290:Ferric Compounds; D005583:Fourier Analysis; D008401:Gas Chromatography-Mass Spectrometry; D010084:Oxidation-Reduction; D010455:Peptides / Q000737:chemistry*; D011522:Protons
D000596:Amino Acids; D005290:Ferric Compounds; D010455:Peptides; D011522:Protons