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Electrochemical oxidation and cleavage of peptides analyzed with on‐line mass spectrometric detection
Author(s) -
Permentier Hjalmar P.,
Jurva Ulrik,
Barroso Begoña,
Bruins Andries P.
Publication year - 2003
Publication title -
rapid communications in mass spectrometry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.528
H-Index - 136
eISSN - 1097-0231
pISSN - 0951-4198
DOI - 10.1002/rcm.1090
Subject(s) - chemistry , tyrosine , peptide , mass spectrometry , electrochemistry , cleavage (geology) , hydrolysis , residue (chemistry) , redox , biochemistry , chromatography , organic chemistry , electrode , geotechnical engineering , fracture (geology) , engineering
An on‐line electrochemistry/electrospray mass spectrometry system (EC/MS) is described that allows fast analysis of the oxidation products of peptides. A range of peptides was oxidized in an electrochemical cell by application of a potential ramp from 0 to 1.5 V during passage of the sample. Electrochemical oxidation of peptides was found to occur readily when tyrosine was present. Tyrosine was found to be oxidized between 0.5 and 1.0 V to various oxidation products, including peptide fragments formed by hydrolysis at the C‐terminal side of tyrosine. The results confirm earlier knowledge on the mechanisms and reaction products of chemical and electrochemical peptide oxidation. Methionine residues are also readily oxidized, but do not induce peptide cleavage. At potentials higher than about 1.1 V, additional oxidation products were observed in some peptides, including loss of 28 Da from the C‐terminus and dimerization. The tyrosine‐specific cleavage reaction suggests a possible use of the EC/MS system as an on‐line protein digestion and peptide mapping system. In addition, the system can be used to distinguish phosphorylated from unphosphorylated tyrosine residues. Four forms of the ZAP‐70 peptide ALGADDSYYTAR with both, either or neither tyrosine phosphorylated were subjected to a 0–1.5 V potential ramp. Oxidation of, and cleavage adjacent to, tyrosine was observed exclusively at unphosphorylated tyrosine residues. Copyright © 2003 John Wiley & Sons, Ltd.