title: Enrichment of N-terminal sulfonated peptides by a water-soluble fullerene derivative and its applications to highly efficient proteomics.
abstract: 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 C60 derivative upon using an acidic solution.
authors.affiliation: Department of Chemistry and Center for Electro- and Photo-Responsive Molecules, Korea University, 1, 5-ka, Anam-dong, Seongbuk-ku, Seoul 136-701, South Korea.
authors.forename: Yong Ho
authors.initials: YH
authors.lastname: Lee
authors.forename: Joong-Won
authors.initials: JW
authors.lastname: Shin
authors.forename: Seungwan
authors.initials: S
authors.lastname: Ryu
authors.forename: Sang-Won
authors.initials: SW
authors.lastname: Lee
authors.forename: Chang Hoon
authors.initials: CH
authors.lastname: Lee
authors.forename: Kwangyeol
authors.initials: K
authors.lastname: Lee