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Effects of peptide acetylation and dimethylation on electrospray ionization efficiency
Author(s) -
Cho KyungCho,
Kang Jeong Won,
Choi Yuri,
Kim Tae Woo,
Kim Kwang Pyo
Publication year - 2016
Publication title -
journal of mass spectrometry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.475
H-Index - 121
eISSN - 1096-9888
pISSN - 1076-5174
DOI - 10.1002/jms.3723
Subject(s) - chemistry , acetylation , peptide , electrospray ionization , chromatography , isobaric labeling , derivatization , mass spectrometry , bottom up proteomics , lysine , peptide sequence , proteome , protein mass spectrometry , amino acid , biochemistry , gene
Peptide acetylation and dimethylation have been widely used to derivatize primary amino groups (peptide N ‐termini and the ε ‐amino group of lysines) for chemical isotope labeling of quantitative proteomics or for affinity tag labeling for selection and enrichment of labeled peptides. However, peptide acetylation results in signal suppression during electrospray ionization (ESI) due to charge neutralization. In contrast, dimethylated peptides show increased ionization efficiency after derivatization, since dimethylation increases hydrophobicity and maintains a positive charge on the peptide under common LC conditions. In this study, we quantitatively compared the ESI efficiencies of acetylated and dimethylated model peptides and tryptic peptides of BSA. Dimethylated peptides showed higher ionization efficiency than acetylated peptides for both model peptides and tryptic BSA peptides. At the proteome level, peptide dimethylation led to better protein identification than peptide acetylation when tryptic peptides of mouse brain lysate were analyzed with LC‐ESI‐MS/MS. These results demonstrate that dimethylation of tryptic peptides enhanced ESI efficiency and provided up to two‐fold improved protein identification sensitivity in comparison with acetylation. Copyright © 2016 John Wiley & Sons, Ltd.