Recent studies have shown that N-terminal sulfonation of tryptic peptides by various sulfonating molecules greatly improves their post-source decay processes (e.g., in matrix-assisted laser desorption ionization) or the gas phase fragmentation processes (e.g., in tandem mass spectrometer), enhancing the ability to identify their sequences de novo. In the present work, we have demonstrated that incorporation of water-soluble C60-N,N- dimethylpyrrolidinium iodide selectively precipitates the 4-sulfophenyl isothiocyanate-modified peptide (SPITC-GGYR, SPITC-ASHLGLAR) by forming a noncovalent ion pair to the SO3- group of the SPITC, and thereby the C60 derivative can be utilized to enrich the modified peptide. Electrospray ionization (ESI) mass analyses show that the cationic SPITC-GGYR and SPITC-ASHLGLAR species are well separated from unmodified peptides and the modified peptides are subsequently detached from the C 60 derivative upon using an acidic solution.
Bibliographical noteFunding Information:
This work was supported by grants from the 21C Frontier for Functional Proteomics (FPR-02-A-5) and from Korea Science Foundation (R0405821), and we acknowledge the support of the facility of CRM at Korea University. K L. also thanks the Korea Research Foundation Grant (KRF-2004-003-C00116).
- De novo peptide sequencing
- Liquid chromatography
- N-terminal sulfonation
- Tandem mass spectrometry
- Water-soluble fullerene derivative
ASJC Scopus subject areas
- Analytical Chemistry
- Environmental Chemistry